United States
Environmental Protection
Agency
Water Engineering
Research Laboratory
Cincinnati OH 45268
Research and Development
EPA/600/S2-87/036 July 1987
Project Summary
Relationships Between Water
Quality and Corrosion of
Plumbing Materials in
Buildings
Chester H. Neff, Michael R. Schock, and John I. Marden
A study was conducted on the
interrelationships of corrosion rates,
metal concentrations, and water qual-
ity occurring within galvanized steel
and copper plumbing systems. A com-
prehensive water sampling program
was implemented to quantify the total
metal concentrations and the major
inorganic constituents found in stand-
ing and running water samples. Cor-
rosion rates were measured by using
the ASTM D2688 corrosion tester.
Lead, zinc, copper, iron, and manga-
nese exceeded the MCL in 10.6% to
25.6% of the standing samples and in
2.2% to 16.0% of the running samples
collected. Chrome-plated brass sam-
pling valves were found to contribute
significantly to the lead, zinc, and
copper contents of the samples. Cad-
mium did not exceed 0.0005 mg/L in
any sample. During the two years the
sites were operating, significant water
quality variations were noted in the six
public water supplies investigated.
Multiple linear regression analyses of
the data were unsuccessful because of
the exceedingly large numbers of
variables encountered under uncontrol-
lable field conditions.
This Project Summary was devel-
oped by EPA's Water Engineering
Research Laboratory, Cincinnati, OH,
to announce key findings of the
research project that is fully docu-
mented in two separate volumes of the
same title (see Project Report ordering
information at back).
Introduction
Corrosion has been a long-standing
and serious problem in public water
supply distribution systems. The poten-
tial health effects of corrosion led to
federal regulations establishing maxi-
mum contaminant levels (MCL's) for
certain metal concentrations in drinking
water. The regulations state that water
supplies should be noncorrosive to all
plumbing materials. Though some
researchers have attempted to identify
or predict which waters are corrosive,
none have found a universally acceptable
identification method that considers all
piping materials and conditions of expo-
sure. Some of the controversy in estab-
lishing the Secondary Drinking Water
Regulations was in defining noncorro-
sive water and acceptable methods for
determining the corrosivity of water.
Two materials that have found wides-
pread use in plumbing systems are
copper and galvanized steel pipe. Expe-
rience has shown that both materials
offer good corrosion resistance to drink-
ing water when the materials are prop-
erly selected and installed. However,
many corrosion failures have been
documented for both copper and galvan-
ized steel piping. The impact of these
corroded materials on water quality has
not been adequately investigated. Brass
valves, lead-based solders, bronze
meters, and other fittings associated with
copper and galvanized steel also make
significant contributions to soluble or
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particulate metal concentrations in
drinking water.
The ASTM D2688, Corrosivity of Water
in the Absence of Heat Transfer (Weight
Loss Methods), Method C was developed
by the Illinois State Water Survey (ISWS)
in 1955 and has been used extensively
in state facilities. The method has been
a reliable indicator for corrosion and/or
scale deposition, and it has been used
primarily to indicate the effectiveness of
various water treatment programs.
Attempts were made by the ISWS to
correlate the mineral content of the
water supplies with the observed corro-
sion rates for copper and galvanized
steel. The correlations met with only
limited success because important
chemical parameters were not deter-
mined or evaluated.
Complete water chemistries are
required for many water supplies if
significant correlations are to be found
between the water quality parameters
and the corrosion rates of metals. Both
corrosion-inhibiting and aggressive
influences have been reported for var-
ious constituents of drinking water. The
chemical constituents commonly cited as
influencing the corrosivity of water are
calcium, alkalinity, pH, carbon dioxide,
sulfate, chloride, dissolved oxygen, silica,
temperature, and dissolved solids. Other
constituents, such as chlorine, organics,
and polyphosphates, are also suspected
to influence the corrosivity of water.
Interaction among the various influences
can be observed only by prolonged,
complicated laboratory testing or by
determining the corrosivity of water in
real distribution systems.
Project Objectives
The principal objective of the corrosion
study was to determine the influence of
various water quality characteristics on
the corrosion rates of galvanized steel
and copper pipe specimens installed in
the potable water systems of residences
and large buildings. A second objective
was to monitor the trace metal concen-
trations contributed by galvanized steel
and copper plumbing materials to the
drinking water.
Methods
Because of cost limitations, the inves-
tigation was limited to six public water
supplies in Illinois representing both
groundwater and surface water sources.
Each water supply used various water
treatment methods that included lime
softening, ion-exchange softening, pol-
yphosphate, and silicate programs.
The 19 corrosion test sites selected for
the study were located in different
sections of the distribution system of
each water supply. A planned-interval
corrosion test was considered the best
procedure for evaluating the effects of
time and water corrosivity on the cor-
rosion of metals. Corrosion specimens
prepared according to ASTM D2688,
Method C, are easily adapted to the
planned-interval method of evaluation.
Installing two of the ASTM corrosion test
assemblies (each containing two corro-
sion specimens) at each test site, and
replacing each of the specimens in turn
with another specimen at 6-month
intervals during the corrosion study
provided seven weight loss measure-
ments, each representing a different
period during the study. The use of
duplicate specimens was considered and
would have provided useful information,
but the additional plumbing and handling
costs prohibited their installation.
Total zinc, copper, lead, iron, manga-
nese, and cadmium concentrations were
determined for both flowing and non-
flowing samples collected from taps in
the buildings where corrosion test sites
were located. Water samples were
collected for a complete chemical anal-
ysis at 2-week intervals throughout the
corrosion study. To evaluate the reliabil-
ity of the data and to improve the
accuracy of interpretation, additional
studies were performed at some of the
sites to assess the rates of polyphosphate
reversion, the contribution of metals
associated with suspended particulates
to the total metal load, and the contri-
bution of the chrome-plated brass sam-
pling taps to the observed metal levels.
On completion of the data collection
phase of the corrosion study, the water
quality, corrosion, and trace metal data
were evaluated by a multiple linear
regression method in an attempt to
identify significant factors influencing
the corrosivity of water.
Sample Collection and
Analysis
Sampling procedures were demon-
strated, documented, and standardized
before the study began because ISWS
field personnel were responsible for
sample collection at only five sites. These
experts visited the remaining sites every
6 weeks to monitor compliance with the
specified procedures.
At corrosion test sites located in homes
or buildings, water samples were col-
lected from the cold water tap before
early morning use. The simulated cor-
rosion test loops were regulated with
times and solenoid valves to enable
sample collection at convenient times
and to control the running and standing
intervals.
Water samples were first taken from
the sampling tap immediately following
the galvanized pipe loop to preserve the
nonflowing conditions in the copper
section.
At all corrosion test sites, water
samples were collected from a chrome-
plated brass faucet or service tap. Screen
filters were removed from the faucets
before sampling. The first 50 to 100 mL
of water was collected from the tap for
a temperature measurement of the
nonflowing sample. The next 125 mL of
water drawn from the tap was collected
in a 125-mL polyethylene bottle contain-
ing 25 ml of 1:1 nitric acid for use in
determining the metal concentrations of
the standing water in the test loop.
The sampling valve was then opened
to allow approximately 0.5 gpm of water
to flow to waste until the water temper-
ature appeared stable and representative
of the distribution water. The tempera-
ture of the running sample was recorded,
and a second 125 mL of water was
collected in a polyethylene bottle con-
taining nitric acid. This second sample
was for use in determining the metal
concentrations of the flowing water. Two
polyethylene sample bottles (one 125-mL
and one 500-mL, each containing 1 mL
of concentrated sulf uric acid) and a glass
vial for TOC analyses were filled with the
flowing water from the tap
Free and combined residual chlorine
and pH measurements were made on the
running water after the samples were
collected. Every 6 weeks, dissolved
oxygen was analyzed in the field as well.
The electrometric pH value, residual
chlorine concentrations, temperature,
and meter reading were then recorded
on a prepared form for enclosure with
the sample bottles.
Styrofoam-msulated cartons contain-
ing two ice packs were used to ship water
samplestothe laboratory. Water samples
from some corrosion test sites were
shipped by 1-day express delivery ser-
vices. Samples from the remaining test
sites were delivered directly to the
laboratory by ISWS or utility sampling
personnel. The water samples were
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refrigerated until time of shipment if
delays were experienced.
Upon receipt of the water samples in
the laboratory, the 500-mL unpreserved
samples were filtered and immediately
analyzed for alkalinity. When two sites
were located in tandem, only one of the
unpreserved samples was taken for
analysis because of time and cost
constraints. Every tenth sample (as
received) was split into duplicates to use
as precision quality controls.
Analyses for trace metals (iron, zinc,
manganese, copper, lead, cadmium),
major cations (calcium, magnesium,
sodium, potassium), and major noncar-
bonate anions (chloride, sulfate, nitrate)
were performed by the Analytical Chem-
istry Unit of the State Water Survey.
Analytical rechecks of suspicious
anion values were performed with
somewhat different procedures to verify
freedom from interferences. Quality
control checks included visual inspection
of analytical reports, ion balance com-
putations, submission of U.S. Geological
Survey (USGS) and U.S. Environmental
Protection Agency (EPA) reference
standards as knowns and unknowns, and
use of the aforementioned split samples.
Some special studies were conducted
to determine whether the trace metal
levels were attributable to particulate
material or to dissolved species. The
study was complicated by the inability to
separate the metal contribution from the
sampling taps, and definitive conclusions
could not be drawn
Data Evaluation Methods
Following checks of analytical accu-
racy and internal consistency, the ana-
lytical data for the major ionic constit-
uents (plus silica) were put into the
WATSPEC3 computer aqueous equili-
brium chemistry speciation model to
compute the saturation states of several
important film-forming solids, aggressiv-
ity parameters such as Larson's ratio
(chloride plus sulfate to bicarbonate), and
the free COz concentration. The program
makes corrections for complexation and
ion pairing of major water constituents.
The absence of analytical speciation and
thermodynamic data for polyphosphate
species made many of the computations
inaccurate for the polyphosphate-
containing systems. Thus they were not
included in the overall water chemistry
data base.
The weight losses and calculated
corrosion rates for the ISWS tester
coupons were entered m a separate data
base to be accessed by computer pro-
grams that would find water quality/
corrosivity relationships.
The following three statistical evalua-
tions were performed by using the
statistical analysis system (SAS) on the
University of Illinois IBM 4341*
computer:
1. The relationship of the trace metal
concentrations at each site to the
independent variables (major con-
stituents and physical parameters
such as temperature and velocity)
at each site.
2. The relationship of the trace metal
concentrations to the independent
variables among all the sites.
3. The relationship of the measured
weight losses of the test pipe
specimens to the measured water
quality variables among sites.
Various stepwise linear regression and
general linear model analyses were
performed on untransformed data, but
significant correlations were not
observed. Regressions were not per-
formed for cadmium, iron, and manga-
nese. All cadmium concentrations were
at or below the analytical detection limit.
Many source waters contained consid-
erable iron, so its presence could not be
attributed to corrosion. Manganese is not
a significant component of any of the
piping materials.
Additional Laboratory Studies
Three laboratory studies were con-
ducted during the course of this project
to determine the significance of some
problems that were appearing in the
chemical data. These involved investiga-
tions of (1) polyphosphate hydrolysis
before sample analysis at four sites, (2)
the contribution of zinc, copper, and lead
from the chrome-plated brass sampling
valves at two sites, and (3) the amount
of trace metal (copper, zinc, iron, lead,
cadmium) leaching into solution from
chrome-plated brass taps exposed over-
night to deionized or tap water.
To determine whether prior piping
contamination of new chrome-plated
brass sampling taps could be responsible
for a significant part of the observed trace
'Mention of trade names or commercial products
does not constitute endorsement or recommenda-
tion for use
metal levels, a new test faucet was
installed before the water meter and test
loop 306. A 125-mL standing water
sample was initially taken at this loca-
tion. After 97 days of operation, three
successive 125-mL unfiltered samples
were taken, and this procedure was
continued through the end of the oper-
ation at this site. After 130 days the
chrome-plated brass faucet was replaced
with one of low-density linear
polyethylene.
Tof urther pursue the leaching from the
chrome-plated sampling taps, a 2-week
benchtop experiment was set up. Six new
faucets were rinsed copiously with
deionized water, inverted, and filled to
capacity (approximately 20 mL) with
either tap water or deionized water. The
faucets were sealed with new silicone
stoppers and mounted with finger clamps
on a flexiframe stand in an inverted
position until the next day. After samples
were withdrawn, the silicone stoppers
were rinsed with 1:1 HNOaand deionized
water, the faucets were filled, and the
stoppers were replaced. Water samples
were taken on alternate days for either
lead or cadmium, or zinc, iron, and
copper.
Corrosion Testing Methods
The corrosion test assembly was
reduced in size from 1 in., as specified
by the ASTM D2688 method, to 0.5 in.
to conform with the nominal pipe dimen-
sions encountered in household plumb-
ing systems. The smaller test assemblies
successfully simulated the actual surface
conditions found in a straight length of
pipe where the flow of water is not
distorted. Visual inspection of the cor-
rosion specimens and the associated
piping of the test loop after 2 years of
exposure showed that the interior sur-
faces were identical in appearance.
Construction details for the smaller test
assemblies will be provided to ASTM for
inclusion in ASTM Method D2688,
Corrosivity of Water in the Absence of
Heat Transfer. An estimate of procedure
variability for the ASTM D2688 method
is presented for the first time.
Results
Corrosion Data
The corrodibility of both copper and
galvanized steel decreased during the
24-month exposure in the more aggres-
sive public water supplies. This decrease
is attributed to the formation of films that
reduce the rate of corrosion. In less
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aggressive water supplies, the corrodi-
bility of the metals remained relatively
constant at low corrosion rates,
indicating a slow development of surface
films.
The weight loss data for galvanized
steel specimens were more erratic than
similar data for copper specimens. This
result was attributed to the spotty nature
of the surface film on the galvanized steel
and to the uniform, continuous surface
film on copper. The use of multiple
specimens for each interval of exposure
would have been beneficial in reducing
the variance in the galvanized steel
corrosion data.
For a single corrosion measurement to
provide reliable information on the
corrodibility of copper or galvanized steel
in public water supplies, the minimum
exposure period should equal or exceed
12 months for copper and 18 months for
galvanized steel.
The weight loss data for copper cor-
rosion specimens indicated that the
Dwight Correctional Center water supply
was the most aggressive. Here corrosion
rates ranged from 3.6 to 1.4 milligrams
per square decimeter per day (mdd) for
6- and 24-month exposure intervals,
respectively. The distinguishing charac-
teristics of this water supply were very
high concentrations of chloride, sulfate,
sodium, and (consequently) total dis-
solved solids.
Water from Springfield, Illinois, was
the least aggressive toward copper
materials, with corrosion rates ranging
from 0.4 to 0.2 mdd for 6- and 24-month
exposure intervals, respectively. This
supply was characterized by a high pH,
low alkalinity, high dissolved oxygen,
high chlorine, and high nitrate content.
Champaign, Illinois, had the water
supply that was least aggressive toward
galvanized steel materials, with galvan-
ized steel corrosion rates ranging from
0.6 to 0.9 mdd for all seven corrosion
specimens. This water supply is a lime-
soda-softened supply in which the
Langelier index is maintained near +0.4
and mineral content is moderate in
concentration.
The weight loss data for galvanized
steel corrosion specimens indicated that
the City of Carbondale, Dwight Correc-
tional Center, and City of Dwight water
supplies were equally aggressive toward
galvanized steel. Corrosion rates ranged
from 6.3 to 2.8 mdd for 6- and 24-month
exposure intervals, respectively. The
galvanized steel weight loss data must
be evaluated with caution, as the cor-
rosion of the zinc surface was not
uniform and accounted for a large
variance in weight loss data for
galvanized specimens.
The corrosivity of the water supplies
(evaluated by the planned interval test
method) did not change significantly as
a result of major fluctuations in water
quality of short-term or cyclic nature. The
varying concentrations of several chem-
ical constituents known to influence the
corrosivity of water were apparently
averaged out over the long exposure
interval.
A change in the corrosion treatment
program in the Carbondale, Illinois, water
supply from a zinc polyphosphate pro-
gram to a pH control program resulted
in a pH increase from 7.0 to 8.3 and
reduced the corrosivity of the water. The
change in corrosivity was more signif-
icant for galvanized steel than for copper
plumbing.
The corrosivity of the City of Dwight
water supply decreased significantly
during the last 18 months of the study.
Total copper concentrations of samples
collected from a copper plumbing system
installed in this water supply also
decreased, which confirmed the reduc-
tion in corrosivity. The reason for the
decrease in corrosivity was not identified,
and apparently it was due to one of the
unknown factors influencing corrosion in
public water supplies.
Copper tubing was susceptible to
increased corrosion at water velocities
exceeding 1.22 m/s. The increase in
corrosion because of velocity was
observed before the actual erosion of
surface films and the exposure of bare
metal occurred.
Copper corrosion rates were not influ-
enced by stagnant water conditions in
the Springfield, Illinois, water supply, but
galvanized steel experienced an appre-
ciably higher corrosion rate for the same
exposure. Very low corrosion rates were
observed for both metals under flowing
conditions in this system.
Quality of Public Water
Supplies
Significant variations in water chem-
istry occurred for the six water supplies
studied, although each supply was
originally conceived of as being stable in
quality. A comprehensive chemical
analysis of water samples collected every
15 days over a 2-year period was
required to observe the real stability of
the water supplies.
The variation in water quality was
caused by changes in water treatment
programs, changes in operational proce-
dures, and unanticipated equipment
failures. Excursions in water quality were
observed to be both random and cyclic,
with cyclic variations occurring at 3-day,
monthly, or seasonal intervals. Random
changes in water quality occurred when
equipment failed or when a major change
was made in the treatment program.
The surface water supplies expe-
rienced normal seasonal changes in
chemical content and temperature.
However, major fluctuations in water
quality were observed in groundwater
supplies using multiple wells when
various wells were put into or taken out
of operation. An increased sampling
frequency is required to observe the
cyclic fluctuations in water quality.
Water supplies with multiple sampling
sites showed no evidence of a significant
change of water chemistry within the
distribution systems, although corrosion
tests indicated a difference in corrosivity.
At the Fox Developmental Center water
supply, a microbiologically mediated
change was presumed to slightly
increase the nitrate concentration and
reduce the phosphate concentration
during the filtration and softening
process.
Variations in water quality appear to
be commonplace in public water supp-
lies. Change in water chemistry may
adversely influence the corrosivity of the
water supply and therefore should be
controlled whenever possible.
Total Metal Concentrations of
Samples
The maximum contaminant level
(MCL) for iron was exceeded in 25.6%
of the standing water samples and in
16.0% of the running water samples.
Manganese exceeded the MCL in 14.5%
of the standing samples and 11.6% of
the running samples.
The naturally occurring iron or man-
ganese content of the water source was
observed to be more significant than
corrosion processes or water quality in
influencing the total iron or manganese
concentrations in samples. The presence
of polyphosphate in the water supplies
was observed to complex both iron and
manganese, maintaining the concentra-
tions above the MCL in some supplies
Cadmium concentrations were very
low in all samples, both running and
standing. Most samples were below the
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minimum detection limit of 0.3 /ug/L for
cadmium. The MCLfor cadmium was not
exceeded by any sample collected during
the study, with the maximum observed
concentration being 4.8 fjg/L cadmium.
The zinc, copper, and lead concentra-
tions of the water samples were found
to be associated with corrosion in
systems containing either copper or
galvanized steel plumbing materials,
although multiple linear regression
models were unable to identify any
significant relationships between metal
concentrations and water quality.
The MCL for lead was exceeded in
17.1% of the standing samples and in
3.1% of the running samples (Figures 1
and 2). The running samples exceeding
the MCLfor lead were collected from one
galvanized and five copper plumbing
systems. The corrosion of lead-tin solder
and the brass sampling valves was
responsible for the lead content of
samples.
Copper concentrations exceeded the
MCL in 10.6% of the standing samples
and 4.5% of the running samples. Zinc
exceeded the MCL in 11.8% of standing
samples and 2.2% of the running
samples.
The concentrations of copper, zinc, and
lead in both standing and running
samples generally decreased over the
24-month sampling period and
approached an apparent mean concen-
tration plateau around which the metal
concentrations fluctuated. Before reach-
ing the concentration plateau, the metal
content fluctuated over a wide concen-
tration range from sample to sample. The
overall distribution of the trace metal
concentrations appeared to be approxi-
mately log-normal rather than Gaussian.
In one water supply, the metal con-
centrations sharply increased during the
latter stages of the study after apparently
attaining stable concentrations. Similar
observations have been made in Seattle,
Washington, although the possible metal
contribution by sampling valves was not
considered.
The total metal concentrations in
samples were influenced by other factors
such as piping configurations before the
sampling valve, quantity and rate of
flushing before sample collection, and
water quality.
Additional Laboratory Studies
In the polyphosphate hydrolysis study,
substantial changes were observed in
the concentration of orthophosphate
over time at two of the sites examined.
60 r
55 -
Figure 1. Percent of standing water samples exceeding the MCL for lead.
25 r
20-
15-
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The conclusion reached was that the
orthophosphate data from these sites are
probably not very accurate. No quantita-
tive correction could be applied to the
data collected before or after discovery
of the problem.
In the study of new faucets to deter-
mine whether old piping or new chrome-
plated brass sampling taps were respon-
sible for the observed trace metal levels,
the data (Table 1} clearly show that the
chrome-plated sampling tap contributed
large amounts of lead and zinc and a
somewhat smaller amount of copper and
iron to the standing samples. The con-
tamination decreased with time but was
still considerable after more than 5
months. The elevated zinc values for the
first 125-mL samples with the polyeth-
ylene faucet represent a contribution
from the relatively new, short, galvanized
section. These data are particularly
enlightening because the low metal
levels shown with the plastic tap corrob-
orate the low corrosion rates measured
in the weight-loss coupon tests. The
metal levels obtained during the main
portion of the study seemed unusually
high compared with the measured cor-
rosion rates. The low lead levels indicate
insignificant contamination from the
galvanized pipe coating.
Results from the 2-week benchtop
experiment with new faucets showed
that extremely high levels of lead were
leached from the tap, even after 2 weeks.
The MCL was exceeded by all samples
taken. A small amount of cadmium was
removed in the first equilbration from the
taps containing Champaign tap water,
but it was not detectable afterwards.
More cadmium was removed by deio-
nized water, and leaching was contin-
uing at detectable levels after 2 weeks.
Iron leaching was odd in that more was
generally taken into the tap water than
the deionized water. As expected, there
was considerable zinc leaching with both
water types, although there was less
from the faucets containing tap water.
The leaching of copper was similar in the
two water types and showed a fairly
consistent level after about 4 days.
These experiments conclusively dem-
onstrated that chrome-plated brass
sampling taps can be a considerable
source of readily leachable lead and zinc,
when lead solder, lead pipes, and gal-
vanized pipes are not present. The use
of such materials might constitute a
health risk under some conditions, and
they can render data from corrosion
studies such as this difficult or impos-
sible to interpret in a framework of
relating analyzed metal levels to corro-
sion rates, mechanisms, or pipe
solubility.
Conclusions
Public water supplies experience
variations in water quality that may affect
the corrosion of plumbing materials and
the concentration of trace metals found
in drinking water. Statistical analyses of
the water quality and corrosion data
failed to identify any meaningful relation-
ships because of the variation in quality.
There are more factors and interrelation-
ships affecting corrosion than can be
taken into account by simple statistical
regression models. Controlled laboratory
studies are necessary for pursuing
correlations between water quality,
corrosion rates, and trace metal
concentrations.
Corrosion of plumbing materials was
responsible for the lead, copper, and zinc
concentrations found in drinking water.
Iron and manganese concentrations
were primarily derived from naturally
occurring substances in the source.
Application of polyphosphate to the
water supply complexed both iron and
manganese and may have partially
solubilized corrosion products of lead,
copper, and zinc. Cadmium concentra-
tions were not significantly influenced by
the corrosion of galvanized steel or
copper plumbing materials. Chrome-
plated brass valves, commonly used for
sampling, contributed significant quan-
tities of lead, copper, and zinc to water,
particularly in standing samples. The
corrosion of lead-tin solder in copper
plumbing also contributed to the lead
content of drinking water as reported in
previous studies; however, the contribu-
tion of lead by common household
faucets may not have been recognized
or differentiated in past studies. Lead,
copper, and zinc concentrations exceed
the MCL in samples collected from new
plumbing systems at a greater frequency
than MCL's are exceeded in older sys-
tems. In more aggressive waters, the
metal concentrations of water from new
plumbing decrease gradually for several
months before reaching a minimum
concentration plateau. In a few instan-
ces, the metal concentrations exhibited
an initial decrease, followed by a gradual
increase which eventually exceeded the
initial concentrations. Proper flushing of
plumbing prior to use will reduce the
occurrence and concentration of trace
metals in drinking water.
Corrosion rate measurements, mad<
by using the ASTM D2688 corrosioi
testers and the planned interval tes
method, were effective in assessing thi
corrosivity of the water and the corrod
ibility of exposed plumbing materials
Under controlled field conditions, th<
procedures provided reliable informatior
on the effects of treatment and change;
in water quality on corrosion rates durmc
long-term (>6-month) test intervals
Short-term variations in treatment oi
water quality are not detected by the
testing procedures used in this study.
Recommendations
1. A standard procedure should be
adopted for determining anc
reporting corrosion measurements
in public water supplies. The
planned interval test method
which compares the weight loss ol
specimens over various time
frames, is the ideal approach foi
detecting significant changes in
the corrosivity of potable water.
The conversion of weight loss
values to corrosion rates assumes
a linear relationship with time.
Such conversions are applicable in
controlled environments where the
corrodibilityof a metal is of interest.
Satisfactory weight loss measure-
ments are obtained by the ASTM
D2688 method for either purpose,
but multiple corrosion specimens
are recommended for each test
interval.
2. A procedure should be developed
to produce instantaneous mea-
surement of corrosion rates and to
detect short-term variations in the
corrosivity of public water supplies.
3. The trace metal content of drinking
water was strongly influenced by
abnormalities in the sampling
process; sampling protocols should
therefore be developed to meet the
specific requirements of environ-
mental health studies, corrosion
studies, or water quality studies.
4. The impact of brass, bronze, and
other copper alloy plumbing mate-
rials on the trace metal content of
drinking water should be given
high priority in future studies.
Chrome-plated brass faucets were
found to be a major source of lead,
copper, and zinc concentrations
found in the public water supplies
-------
Table 1.
Metal Concentrations (mg/L) in Successive 125-mL Unfiltered Standing Samples from the Sampling Tap Installed Before Site
306
Zinc
Copper
Lead
Iron
Date
3/8/83
4/6/83
4/14/83
4/21/83
5/3/83
5/14/83
5/24/83
6/13/83
6/22/83
6/27/83
7/12/83
7/16/83
7/21/83
8/5/83
8/15/83
8/22/83
Elapsed
Days
1
30
38
45
57
68
78
98
107
112
127
131
137
151
161
168
1
1.30
0.99
2.09
2.66
2.08
1.98
0.65
1.10
1.01
0.75
0.68
0.30
0.22
0.35
0.55
0.46
2
—
—
—
—
—
—
—
0.41
0.42
0.28
0.69
0.20
0.16
0.26
0.22
0.21
3
—
—
—
—
—
—
—
0.48
0.30
0.26
0.25
0.24
0.14
0.22
0.01
0.17
1
0.73
0.31
0.18
0.77
0.06
0.07
0.29
0.04
0.06
0.08
0.03
<0.01
<0.01
<0.01
<0.01
<0.01
2
—
—
—
—
—
—
—
0.03
0.03
0.02
0.04
3
—
—
—
—
—
—
—
0.04
0.04
0.04
0.04
1
0.099
0.056
0.059
0.060
0.031
0.075
0.021
0.030
0.019
0.015
0.013
2
—
—
—
—
—
—
—
0.011
0.008
O.Q05
0.023
3
—
—
—
—
—
—
—
0.008
0.005
0.004
0.004
1
0.11
0.03
0.28
0.93
0.29
0.32
0.09
0.42
0.36
0.52
0.28
2 3
—
—
—
—
—
—
—
0.07 o.;o
0.05 <0.06
0.06 <0.07
0.72 0.05
7" // d
<0.01 <0.01
<0.01
<0.01
<0.01
-------
Natural Resources and the University of
Illinois under the sponsorship of the U.S.
Environmental Protection Agency.
Chester H. Neff and Michael P. Schock are with the Illinois Department of
Energy and Natural Resources. Champaign. IL 61820; and John I. Marden
is with the University of Illinois, Urbana. IL 61801.
Marvin C. Gardels is the EPA Project Officer (see below).
The complete report consists of two volumes, entitled "Relationships Between
Water Quality and Corrosion of Plumbing Materials in Buildings:"
"Volume I. Galvanized Steel and Copper Plumbing Systems," (Order No. PB
87-192 548/AS; Cost: $18.95)
"Volume II. Appendices," (Order No. PB 87-192 555/AS; Cost: $18.95)
The above reports will be available only from: (costs subject to change)
National Technical Information Service
5285 Port Royal Road
Springfield, VA 22161
Telephone: 703-487-4650
The EPA Project Officer can be contacted at:
Water Engineering Research Laboratory
U.S. Environmental Protection Agency
Cincinnati. OH 45268
United States
Environmental Protection
Agency
Official Business
Penalty for Private Use $300
EPA/.600/S2-87/036
Center for Environmental Research
Information
Cincinnati OH 45268
BULK RATE
POSTAGE & FEES
EPA
PERMIT No G-3
CHICAGO
60604
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