IRRIGATION CONTROLLERS
'TIMERS FOR THE HOMEOWNER
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Recommended Wafer Saving Features
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IRRIGATION CONTROLLERS
TIMERS FOR TH6 HOMEOWNER
Recommended Water Saving Features
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While controllers come in all types of shapes and sizes, the most important features
are how well the)? can be programmed to handle diverse landscape and weather conditions.
Disclaimer
This booklet was originally developed by the East Bay Municipal Utility District
(EBMUD), Oakland, California and is being published by EPA with EBMUD's
permission for informational purposes only. EPA publication does not constitute an
endorsement of any products or services identified in the booklet, nor of EBMUD.
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Preface
The U.S. Environmental Protection Agency published this booklet because of the
importance that efficient landscape water use has for the environment and the economy.
The most obvious benefit of efficient landscape water use is conservation of water
resources. In most situations the water we use to irrigate landscapes is treated drinking
water. By reducing the amount of drinking water used for landscape irrigation, we
reduce the burden on water treatment facilities and often can defer future facility costs.
A small but growing number of municipalities have reduced drinking water facility
needs by building a separate water reuse system to supply reclaimed wastewater to
homeowners for landscape irrigation and other non-potable uses. In either case, irriga-
tion water should be used efficiently. This booklet is designed to help the homeowner
understand and select the right controller for their individual needs and use it properly
the key to efficient irrigation.
Efficient landscape water use can have many environmental and economic benefits:
Lower water bills from reduced water use.
Extended life for water system infrastructure (e.g. treatment plants, pipe systems),
thus reduced taxpayer costs.
Reduced runoff of storm water and irrigation water that carries topsoil, fertilizers,
and pesticides into lakes, rivers, and streams.
Conservation of natural resources and preservation of habitat for plants and wildlife
such as fish and waterfowl.
Decreased energy use (and air pollution associated with its generation) because less
pumping and treatment of water is required.
Acknowledgement
Special recognition goes to Dick Bennett and Richard Harris of the East Bay Municipal
Utility District for their efforts in producing this booklet.
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Foreword
This brochure is a cooperative effort sponsored by members of both the water and land-
scape industry to promote efficient landscape water use. The purpose of this brochure is
to highlight important features of a controller (also called a timer or clock) that allow
for proper watering schedules. Since many people are somewhat mystified or intimidat-
ed by these devices, hopefully, this brochure will help when making the decision of
which controller to obtain. The main point to keep in mind is that the key to water-
ing efficiently is to obtain a controller that can handle diverse landscape and
weather situations and then to program it properly. This message is so important;
it is repeated again in the text.
Also discussed in this brochure is information on a new generation of controllers,
called ET based controllers, that automatically change water schedules based upon
past or historic climate conditions for a given region.
We encourage you to contact your local water agency or landscape company to obtain
more information on how to improve landscape water use efficiency. For any technical
assistance you may need with your controller, contact the manufacturer.
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Importance of Irrigation Controllers
A large part of our household water use goes to watering our landscape and many
households rely on automatic in-ground irrigation systems to accomplish this. One of
the most important components of an automatic in-ground irrigation system is the irriga-
tion controller (also called a timer or clock). The controller turns the automated irriga-
tion system on and off at the times you select. In other words, the controller controls
the irrigation system and you control the controller. Having a controller with cer-
tain minimum performance capabilities is vital to efficient watering. The right con-
troller, properly scheduled, can result in significant water savings and lower water bills.
While controllers come in all types of shapes and sizes, the most important features are
how well they can be programmed to handle diverse landscape and weather conditions.
How Does a Controller Work?
An automatic in-ground irrigation system is a collection of pipes, tubing, valves, sprin-
kler heads, and circuitry used to irrigate a landscape. Automatic valves (also called sta-
tions or zones), which control the flow of water to different parts of the landscape, open
and shut upon a signal from the controller. For example, there may be one valve that
controls the water flow to some groundcover, another valve for some shrubs and another
valve for the lawn. Once programmed, the controller determines when, how often, and
how long each valve is open. It controls how much water goes where and when in
your landscape based upon your instructions. The more programming flexibility
the controller has, the more efficiently water can be applied to the landscape.
Why Certain Controller Features are Important
The key to watering efficiently is to obtain a controller that can handle diverse
landscape and weather situations and then to program it properly to meet your
plants' water needs. Let's imagine you have a front yard with three valves that control
the water flow to a sloped lawn area, to several trees, and to a groundcover area. You
desire to water the lawn every third day for the entire month in three short time intervals
of five minutes each and want a 30-minute break between watering to avoid runoff from
the slope. You also desire to water the trees, which are on a drip system, once a month
for two hours. Next, you want to water the groundcover once a week for 30 minutes.
Finally, you don't want to water if it is raining. To accomplish this, your controller
would need the following features: 1) three independent programs, 2) 120 minute station
run times, 3) three start times per program, 4) interval program capability to 30 days,
and 5) rain shut-off device capability (the actual rain shut-off device needs to be
purchased separately).
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Important Water Saving Features
The recommended minimum hardware features for a controller include:
Three independent programs
Station run times from 1 to 200 minutes
Three start times per program
Odd/even, weekly and interval program capability up to 30 days
Water budgeting from 0-200%, in 10% increments, by program
365 day calendar, adjusted for leap year
Non-volatile memory or battery back-up
"Off', "Auto", and "Manual" operation modes without disturbing programming
Rain shut-off device capability
Diagnostic circuitry to notify homeowner when station is shorted or a power
failure has occurred
The above features, discussed in more detail below, are important because they give you
the ability to properly manage your landscape watering.
Multiple independent programs allow watering different parts of the yard on different
days. Station run times determine the upper and lower limit on how long an area can
be watered. While watering times are usually in minutes, a few controllers are capable
of assigning run times in seconds (for potted plants) and hours for drip applications.
Multiple start times allow for repeat watering in the same area on the same day.
Odd/even, weekly, and interval program capability allows for flexibility in deciding
what days to water. For example, a 30-day calendar would allow watering a large tree
once a month. Water budgeting (also known as a percent switch) allows for an increase
or decrease in station run times by a certain percent. For example, during a cool spell,
you may want to decrease watering time by 10% for all programs. This feature allows
for the changing of all station run times within a given program in one easy step. 365-
day calendar allows for the tracking of the number of days in each month throughout
the year. Non-volatile memory retains the set program in case of a power failure.
However, the set start watering times are still affected. For example, a four-hour power
failure where the watering times are set to start at 6 a.m. would result in 10 a.m. start. A
battery back-up is recommended to retain the 6 a.m. watering time. Controllers with
only volatile memories would both lose their set program and have the watering start
time affected. For controllers with volatile memories, a battery back-up would retain
both the set program and the set watering times. Rain shut-off device capability (and
rain shut-off device) is used to automatically override the call for water during rain
events. (The actual rain shut-off device needs to be purchased separately since it is not
included with the controller.) Diagnostic circuitry to notify the homeowner when a sta-
tion is shorted or a power failure has occurred is useful so that the controller can be
checked for any changes or problems as soon as possible.
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In addition to the above hardware, programming instruc-tions, technical support phone
numbers, and irrigation scheduling information are important resource tools.
Check with your local water utility, irrigation supply company, or landscape professional
for local watering guidelines.
Options! Controller Features
Besides the above mentioned recommended controller features, several desirable but
optional features include "pause times" and "soak cycles". The "pause time" feature
allows for some time to elapse before watering different stations within a program. This
feature allows time for a control valve to completely close before the next valve opens
ensuring more uniform pressure and thus better uniformity of coverage. For those on
well water, this feature may allow time for the level in the well to recover before the
next irrigation cycle. The "soak cycle" allows for short, multiple watering cycles. This
feature can be used either before a normal irrigation cycle to reduce runoff or for multi-
ple, short waterings of a given area.
Controller Warranty
Ask about the warranty on any controller you are considering. The length of a product
warranty is often linked to quality and many controller manufactures are offering
warranties in the 2-5 year range: the longer, the better.
Other Important Components of an Efficient Irrigation System
Besides obtaining an irrigation controller with the recom-mended features, there are
other irrigation components that should be used with irrigation systems to save additional
water. Control valves control the flow of water to different parts of the landscape and are
used for the separate watering of plants with different watering needs. Check valves can
be installed in sprinkler heads to prevent water from draining out of the irrigation line
when the water is turned off and are most useful on sloped landscapes. Rain shutoff
devices can be wired to a controller to shut off the system when it is raining. Moisture
sensors can be wired to control valves to override the call for water if they "sense" that
enough moisture is already present in the soil. Moisture sensors, therefore, "monitor" the
irrigation schedule for over watering. Drip or bubbler irrigation can be used to irrigate
slowly and minimize or eliminate evaporation, runoff and overspray. Finally, low precip-
itation spray, stream, and sprinkler heads with matching precipitation rates can
dramatically improve efficiency. It is important to note that automatic irrigation sys-
tems, if not properly managed, can waste a lot of water. Always be mindful that YOU
are the "brains" behind your irrigation system scheduling and YOU control the controller.
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AUTOMATIC IRRIGATION SYSTEM
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Plants require the most water during the summer and little or no water in the winter. After
July, plants need less water each month, and by November, often little or no irrigation is
required until March or April. Then, plant water needs increase each month through July.
The chart below compares the typical month to month average percentage changes in
your landscape's water requirement to the July requirement. For example, the landscape's
water requirement in May is twice that of April but only 60% of the July requirement.
This chart demonstrates the importance of regularly changing your irrigation schedule.
Note that by the end of September, your landscape will need only about half of the water
it needed in July. Since this chart is based upon the change by month in a plant's water
need, local precipitation will, of course, affect how much supplemental irrigation is need-
ed. Check with your local water agency or Cooperative Extension office for specific
monthly water requirements for your landscape.
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Apr
May Jun Jul
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Besides proper irrigation system design and scheduling, water use efficiency in the land-
scape can also be increased through appropriate use of plant material, soil preparation,
and proper horticultural practices (maintenance).
Extensive use of plants suited for the climate of the region should be considered for
your landscape. Plants should be grouped, as much as practical, according to their water
requirements. Proper horticultural practices that include regular pruning, weeding, lawn
aerating and dethatching, and the use of mulches and fertilizers should be followed.
For more detailed information regarding water saving opportunities in the landscape
contact your local water agency, irrigations supply store, or landscape professional.
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A new generation of controllers, called ET based I
controllers, has recently become available that i
uses a measure of plants' water requirement called
"Evapotranspiration" (ET). ET is used to schedule ,:,' jjjl m
watering based on historical climate for a locale and ' m %
is a measure of the rate of a plant's water requirement "
that involves plant transpiration and soil evaporation. I, Two of ET
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The ET rate is dependent on such weather factors as sun light, temperature, wind, and
humidity, and varies throughout the day, by day, by week, etc. ET is usually measured in
inches per day and is highest in the summer and lowest in the winter. In fact, often times
no watering is needed in the winter because many plants are dormant and because winter
precipitation meets or exceeds the plants' water requirement (ET rate). Some ET con-
trollers have the watering schedule programmed into their computer chip based upon
historical ET data for a given region. Other ET controllers can change the water schedule
weekly based on the past week's weather for a region via a radio signal.
Why is an ET based controller important in watering schedules? By scheduling watering
based on ET rates, plants can receive the required amount of water to remain healthy
without over or under watering since the ET controller adjusts the watering schedule
automatically. Thus, the homeowner doesn't have to guess what the optimum watering
schedule might be throughout the year. Because many homeowners don't adjust a con-
troller's watering schedule often enough, ET controllers have the potential to increase
watering efficiency.
Some of the new ET controllers also have temperature and rain sensors that further
adjust the watering schedule when large differences from historical climate occur such
as during unseasonably hot or cold spells. Ask your local irrigation supplier about the
new ET based controllers.
Sample Wafer Schedule
The chart below shows a sample watering schedule. You can increase or decrease the
amount of water applied to the landscape by changing either the number of start times per
day, the number of minutes per day, or the number of watering days per week. Note in this
example the watering times stay the same but the number of watering days per week
change during the year. Also, note no watering is shown for the winter months. To deter-
mine the appropriate watering schedules for your area, contact your local water agency or
landscape professional. Keep your schedule in your controller for easy references.
Plant
Type
lawn
groundcover
shrubs
trees
Sprinkler
Type
spray
spray
drip
drip
Starrs
per day
2
2
1
2
Minutes
per day
7
7
30
30
Number of Watering
Days per Week:
Fall and Spring
2
.5
.5
0
Number of Watering
Days per Week:
Summer
3
1
1
.5
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California Department of Water Resources
California Landscape Contractor Association
California Urban Water Conservation Council
City of Austin, Texas
City of Santa Barbara
Contra Costa Water District
East Bay Municipal Utility District
Irrigation Association
Johnson County Water District #1
Massachusetts Water Resource Authority
New Mexico Office of the State Engineer
Santa Clara Valley Water District
Southern Nevada Water Authority
Tacoma Water, Washington
United States Bureau of Reclamation
United States Environmental Protection Agency
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