vvEPA

FACT SHEET

EPA's Final Lead and Copper Rule Improvements
Technical Fact Sheet: Tap Monitoring Requirements

October 2024

This fact sheet highlights the changes in the lead and copper tap sampling requirements for community water
systems, non-transient non-community water systems, and States under the final Lead and Copper Rule
Improvements (LCRI). Tap sampling results can trigger systems to take additional actions to reduce lead and
copper exposure, such as reducing the corrosivity of water in a system by installing or re-optimizing optimal
corrosion control treatment (OCCT), or through public education.

What are water systems required to do before sampling under the LCRI?

By the start of the first lead and copper tap monitoring period under the LCRI, all water systems must submit an
updated sampling plan to their State. The plan must include:

•	A pool of tap sampling sites from the highest tier available based on the materials of service lines and
connectors (gooseneck or pigtail) in their service line inventory (refer to Table 1).

•	A list of water quality parameter (WQP) entry point and distribution system sampling locations.

The State may review and require systems to modify their plan, but States are not required to approve the plan
for water systems to use it. However, water systems must collect samples in accordance with the plan.

Where must water systems collect tap samples?

The LCRI revises the tiering criteria to prioritize where tap samples must
be collected based on which sampling sites have the greatest likelihood
of capturing the highest lead levels at the tap (see Table 1). Tier 1
denotes the highest priority tier and Tier 5 the lowest. Water systems
with lead service lines (LSLs) and/or premise plumbing made of lead must
collect all samples from sites served by LSLs and/or with premise
plumbing made of lead (Tiers 1 and 2), if a sufficient number of sites are
available (see text box). Systems without LSLs or premise plumbing made
of lead must collect samples from sites in the highest available tier.

Table 1. Revised Tiering Criteria under the Final LCRI

Water systems do not need to
sample from a site in the
sample plan after a customer
refusal or two outreach
attempts with no response
from the customer. The
number of refusals and non-
response from customers
must be reported to the
State.

Sample Site Tier

Description

Tier 1

Single-family structures (SFS) with premise plumbing made of lead and/or served by an LSL.

Tier 2

Buildings, including multiple-family residences, with premise plumbing made of lead and/or
served by an LSL.

Tier 3

SFS served by a lead connector. SFS served by a galvanized service line or containing
galvanized premise plumbing identified as ever having been downstream of an LSL.

Tier 4

SFS that contain copper premise plumbing with lead solder installed before the effective date
of the State's applicable lead ban.

Tier 5

SFS or a building in which the plumbing materials used at that site would be commonly found
at other sites served by the water system (i.e., representative of sites throughout the

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Sample Site Tier	Description

|	| distribution system).	

What is the sampling protocol under the LCRI?

General Requirements

The LCRI retains the Lead and Copper Rule (LCR) requirement for samples to:

•	Be collected from an interior kitchen or bathroom sink cold-water tap
for residential buildings or an interior cold-water tap from which
water is typically used for human consumption for nonresidential
buildings.

•	Have stood motionless in the plumbing system and/or service line for
at least six hours.

The LCRI requires that:

•	Sample collection instructions cannot direct the sample collector to remove or clean the aerator or flush
taps prior to the start of the minimum six-hour stagnation period.

•	Samples be collected in a wide-mouth bottle that is defined as one liter in volume and has a mouth with
an inner diameter of at least 40 millimeters.

Water Systems with Lead Service Lines

Under the final LCRI, water systems with LSLs must collect an additional fifth-liter sample at the same time as
the first-liter sample (i.e., first-liter- and fifth-liter-paired sample) at sites served by an LSL. The fifth-liter sample
increases the likelihood that samples capture water that has been sitting in contact with LSLs. Both the first- and
fifth-liter samples must be analyzed for lead. The first-liter sample is also analyzed for copper when both
contaminants are required to be monitored (see "When are samples
collected?").

To collect a first-liter- and fifth-liter-paired sample, the sample collector
(e.g., water system or consumer) must:

•	Fill the first numbered wide-mouth sample bottle with tap water.

•	Immediately slide the second bottle under the tap without turning
the water off and repeat the process for bottles three through five
in consecutive order.

Water Systems with No Lead Service Lines

Water systems without LSLs must follow the "General Requirements" described above, collect a first-liter
sample only from the highest available tiered site, and analyze the sample for lead and copper where both
contaminants are required to be sampled (see "When are samples collected?").

When must samples be collected?

Tap monitoring period and tap sampling period

The tap monitoring period determines the frequency that a water system must conduct tap sampling and
ranges from six months to nine years. The tap sampling period is the time period within the tap monitoring
period during which the system must collect the samples. There is one tap sampling period per tap monitoring
period.

Tap samples requested by
consumers and those
collected as follow-up to a
single lead result above
0.010 mg/L do not have to
follow this sampling
orotocol.

TESTING WHERE THE LEAD IS

For homes with lead service lines, the 1st and
5th liter of water must be tested for lead.

FIRST
LITER

FIFTH
LITER

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Systems that must conduct standard monitoring

Beginning January 1, 2028, the following systems must conduct standard
monitoring for at least the next two consecutive six-month tap monitoring
periods:

•	Systems with lead and/or GRR service lines, unless they already follow
the LCRI tap sampling protocols prior to the LCRI compliance date. In the
latter case, the water system can remain on its existing sampling schedule.

•	Systems that exceed the revised lead action level of 0.010 mg/L or copper action level of 1.3 mg/L in their
most recent tap monitoring period as of the LCRI compliance date.

In addition, a system must conduct standard monitoring for at least two consecutive six-month monitoring
periods at any time if it meets any of the following criteria:

•	Exceeds a lead or copper action level.

•	Fails to operate at or above the minimum value or within the range of values for the State-designated
optimal water quality parameters (OWQPs) for more than nine days in any tap monitoring period.

•	Becomes a large water system (i.e., grows to serve more than 50,000 people) and has no corrosion
control treatment (CCT).

•	Is a large water system, has no CCT, and its 90th percentile lead level exceeds the lead practical
quantitation limit (PQL) of 0.005 mg/L.

•	Installs or re-optimizes optimal corrosion control treatment (OCCT) or adjusts OCCT following a
Distribution System and Site Assessment. Systems must continue standard monitoring until the State
designates new OWQPs.

•	State has designated new values for OWQPs.

•	Installs source water treatment.

•	Notifies the State of an upcoming addition of a new source or long-term change in treatment, unless the
State does not require more frequent monitoring.

•	Has no lead or GRR service lines in its inventory but subsequently
discovers such a service line, unless the line(s) are replaced prior to
the start of the next tap monitoring period.

Systems that qualify for reduced tap monitoring

•	Water systems can qualify to conduct tap monitoring annually if they
do not exceed the lead and copper action levels for two consecutive
six-month tap monitoring periods and meet their OWQPs (if
applicable). Systems must sample for lead at the standard number
of sites and for copper at the reduced number of sites.

•	Water systems can qualify to conduct tap monitoring every three
years at the reduced number of sites for both lead and copper if they meet their OWQPs (if applicable)
and:

For systems serving 50,000 or fewer people, they do not exceed the lead and copper action level for
three consecutive years.

For any water system, their 90th percentile lead and copper levels do not exceed the lead PQL of
0.005 mg/L and copper PQL of 0.65 mg/L, respectively, for two consecutive tap monitoring periods.

•	Prior to conducting triennial monitoring, systems must receive a written determination from the State

Standard monitoring
consists of six-month tap
monitoring periods of
January - June or July -
December.

Systems on reduced
monitoring must sample
during the tap sampling
period of June - September,
unless the State has
approved a different tap
sampling period.

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approving triennial monitoring.

• The LCRI did not modify the provisions for systems serving 3,300 or fewer people to qualify for
monitoring every nine years at the reduced number of sites.

How many samples are required?

The final LCRI did not change the minimum number of tap samples that a system must collect (see Table 2).

Table 2. Minimum Number of Required Lead and Copper Samples

System Size (number of
people served)

Standard number of
sites

Reduced number of
sites

<100

5

5

101-500

10

5

501 - 3,300

20

10

3,301 -10,000

40

20

10,001 -100,000

60

30

>100,000

100

50

Is sample invalidation allowed under the LCRI?

The LCRI retains the ability for States to invalidate samples from LCRR with some modifications. Under LCRI,
States now have the authority to invalidate samples that do not meet the site selection criteria (e.g., when sites
of a higher tier were available and were not sampled) and/or the sample collection criteria, including minimum
stagnation time.

What samples must be used to calculate the 90th
percentile levels?

The 90th percentile levels of a system's lead and copper tap samples
are compared against the respective action levels of 0.010 mg/L for
lead and 1.3 mg/L for copper. If a system exceeds either of these
levels, the system must undertake steps to install or re-optimize OCCT
and educate the public. A description of the LCRI modifications to the
90th percentile calculation with examples follows.

First, systems must compile eligible sample results for the 90th
percentile calculation.

•	Samples are eligible to be included if they are: 1) collected
according to the LCRI compliance tap sampling protocol; 2)
collected during the appropriate tap sampling period; and 3)
are from the highest tiers with available samples.

•	The highest sample from each site collected during that tap sampling period must be included. For sites
with LSLs, only the higher of the first- or fifth-liter sample can be included.

Second, systems must calculate the 90th percentile levels according to the system characteristics below:

Systems with Sufficient Tier 1 and 2 sites

• Tier 1 samples are eligible. Only when Tier 1 sites are exhausted can systems include samples from Tier 2,
unless the system has 20% or more of residential sites in Tier 2.

Which samples are included in the 90th
percentile calculation?

Include: Compliance samples and
consumer-requested samples if they
are collected from the highest available
tier(s) and meet the sampling protocol.

Exclude: Samples collected as follow-
up to a single lead result above 0.010
mg/L or after service line replacement.

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•	Samples from Tiers 3 through 5 are not eligible.

•	The 90th percentile levels must be calculated using all eligible sample results.

( |
Example: A system with LSLs serves 10,001 people and is required to sample at 60 sites. The system collects

samples from 62 Tier 1 and 2 sites and samples from 8 Tier 3 sites. All samples meet the sampling protocol

requirements. All available Tier 1 sites are exhausted.

Question: Which samples must be included in the 90th percentile calculation?

Answer:

•	For lead, the higher of the first- or fifth-liter sample result from each of the 62 Tier 1 and 2 sites.

•	For copper, the first-liter sample results from the 62 Tier 1 and 2 sites.

	J

Systems with an insufficient number of Tier 1 and 2 sites

•	Samples from Tiers 1, 2, and the next highest tier(s) (sufficient to supply enough sites to meet the
minimum number of samples required) are eligible. Only when Tier 3 sites are exhausted can systems
include samples from Tier 4, and only when Tier 4 is exhausted can systems include samples from Tier 5.

•	The 90th percentile level is calculated using the highest results from the eligible samples, equal to the
minimum number of samples required (see Table 2).

C	"	I

Example: A system with LSLs serves 10,001 people and is required to sample at 60 sites. The system samples at
a total of 65 sites: 50 Tier 1 and 2 sites, 12 Tier 3 sites, and 3 Tier 4 sites. All samples meet the sampling protocol
requirements.

Question: Which samples must be included in the 90th percentile calculation?

Answer:

•	Since sites from Tiers 1 through 3 are sufficient to meet the minimum number required, Tier 4 samples
are not included.

•	For lead, the highest 60 samples (the minimum number of required samples) from Tiers 1, 2, and 3. For
each Tier 1 and 2 sample, only consider the higher of the first- and fifth-liter sample result.

•	For copper, the highest 60 first-liter sample results from Tiers 1, 2, and 3.

	J

Systems with no Tier 1 and Tier 2 sites

•	Tier 3 samples are eligible. Only when Tier 3 sites are exhausted can systems include samples from Tier
4, and only when Tier 4 is exhausted can systems include samples from Tier 5.

•	The 90th percentile levels for lead and copper must be calculated using all eligible sample results.

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Example: A system with no Tier 1 or Tier 2 sites serves 10,001 people and is required to collect 60 samples. The
system collects a total of 70 samples: 30 samples from Tier 3 sites and 40 from Tier 4 sites. All samples meet the
sampling protocol requirements. All available Tier 3 sites are exhausted.

Question: Which samples are included in the 90th percentile calculation?

Answer:

•	For lead, the first-liter sample results from the 70 Tier 3 and 4 samples.

•	For copper, the first-liter sample results from the 70 Tier 3 and 4 samples.

	J

Systems Collecting Five or Fewer Samples

•	Systems collecting five samples must use the average of the highest and second highest sample results.
This has remained unchanged from the LCR.

•	The LCRI clarifies that systems collecting fewer than five samples must use the sample result with the
highest concentration as their 90th percentile value if they:

1.	Have been approved to collect multiple samples from the same site on different days during the
same tap sampling period; or

2.	Failed to collect the required minimum number of samples.

Disclaimer: This document is being provided for informational purposes only to assist members of the public, States, Tribes, and/or public water systems
in understanding the Lead and Copper Rule Improvements (LCRI). It includes descriptions of regulatory requirements. In the event that there are any
differences, conflicts, or errors between this document and the LCRI, States, Tribes, and/or public water systems should refer to the LCRI. This document
does not impose any legally binding requirements on the EPA, States, Tribes, or the regulated community. Further, this document does not confer legal
rights or impose legal obligations on any member of the public. In the event of a conflict between the discussion in this fact sheet and any statute or
promulgated regulation, the statute and any promulgated regulations are controlling.

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