Agricultural Pumping

Efficiency Program

Pump Efficiency Tests

Helping California Agriculture...

Pump Efficiency Tests

The Agricultural Pumping Efficiency Program

provides subsidized pump efficiency tests to California
agriculture. This brochure explains various aspects of
pump efficiency tests, how they can save you money,
and how you can obtain one. For more information
contact the Program at (800) 845-6038 or log on to
our website at www.pumpefficiency.org.

What is a Pump Test?

A pump test measures various aspects of the pump's
operation. The end result of a pump test is an estimate of the
overall efficiency of your pump and the cost of running it
under the conditions of the test. The test may also give an
indication of water well performance.

Who Does the Pump Testing?

Pump tests may be available from:
Public utilities - using either their own employees or
contract testers
Pump dealers - using their own employees or contract
testers
Independent pump test companies - many of these testers
have a public utility background
To obtain a subsidized pump test under the Agricultural
Pumping Efficiency Program you must use a participating
pump test company. Please call or log on to our web site at
www.pumpefficiency.org for a current list of these
companies.

What Does a Pump Tester Measure?

The tester measures at least four variables:
1. Water flow rate
2. Pumping lift (or inlet pressure)
3. Pump discharge pressure
4. Energy input to the pumping plant
Calculations are performed with the flow, lift, and pressure
measurements and the results are compared to the energy
input. A sample pump test report and an explanation of what
it measures and calculates can be found on page 6.

Why Should I Test My Pump?

Regular pump testing can identify problems before a
breakdown occurs or energy bills climb. This allows you to
perform an objective economic analysis to identify when it
can be profitable to invest in a retrofit or repair. On a new
pump, a test will establish a baseline of performance and
verify that equipment is operating as designed. A typical
analysis of pumping costs derived from a test, along with
explanations of the variables used in the calculations, is shown
on pages 8 and 9.

How Do I Prepare for a Pump Test?

Check with your pump tester about how to prepare for a
pump test. Some testers use flow measurement equipment
that requires an access hole in the pump discharge pipe.
Generally, the pump needs to be off in order to cut the hole
and insert the device. Some measurement devices do not
require this provision.
The pump must be running during the test and there must
be someplace for the pumped water to go. If the pump is in a
water well, the tester will need to run the pump for about 3045 minutes to stabilize the pumping water level.
The pump tester will also need information regarding the
pump's management and design in order to do a complete
cost analysis. Key information will include:
annual acre-feet pumped (or hours of operation)
average cost of energy for the year
intended operating condition
required flow rate
required discharge pressure of the pump
If a water well is running when the tester arrives, he will want
to shut it off and measure the "recovered water level" of the
well. This is valuable information for you that indicates
current well performance.

What Is Needed for Accurate Measurements?

Water flow in a pipe can only be accurately determined if the
location for flow measurement (known as the "test section")
is free from turbulence. Ideally, the test section should be a
run of straight pipe with lengths 8 - 10 pipe diameters
upstream and 2 - 4 pipe diameters downstream of the
measurement point that are free of obstructions or turns (see
the figure below). In addition, access via a sounding tube or a
factory-made hole in the discharge head may be needed to
determine standing and pumping water levels in a well.
2 - 4 Pipe Diameters

8 - 10 Pipe Diameters

This schematic shows an ideal test section:

8 - 10 pipe diameters upstream
2 - 4 pipe diameters downstream, clear of obstructions
or turns
(For a 6" diameter pipe this would mean 48" to 60" upstream
and 12" to 24" downstream clear.)

Can Two Pumps Be Tested Together?

Pumping plants may be designed with a well pump to lift the
water to the surface and a booster pump to supply pressure to
the irrigation system. Typically, the well pump is tested first
and then the well/booster combination is tested. The booster
pump efficiency is determined by subtracting the inlet
pressure into the booster. In some cases, amperage and
voltage readings for each pump are taken to determine input
horsepower.

What is a Multi-Condition Pump Test?

A pump can operate with a wide variety of flow and pressure
outputs. A multi-condition test consists of making the
required measurements at several different flow rates. This
type of test is useful in situations where the pump design is
unknown or where aquifer or discharge conditions have
changed substantially.

How Do I Use the Data from a Pump Test?

You should have a copy of your pump's original pump
performance curve. Record the results of each pump test and
compare them to that curve and to previous tests. Consult
with your pump dealer to determine if a pump adjustment or
repair will be profitable.
IMPORTANT! The pump test results are only valid for the
combination (or combinations) of flow and total lift measured.
You should try to ensure that the test conditions are as close as
possible to typical running conditions.

How Often Should I Test My Pump?

A pump should be tested every 1 to 3 years depending on the
annual usage and severity of operating conditions. For
example, you might want to test a well that is pumping a lot
of sand every year. On the other hand, a booster pump
supplied by clean water might only be tested once every 2 or
3 years.

How Can I Obtain a Pump Test?

Log on to the Program's web site or call one of the offices
listed below to obtain a list of participating pump test
companies. You can use any of the companies on this list just call them to arrange the time of the test. They will handle
all of the paperwork and the rebate for the pump test will be
paid directly to them.

Where Can I Get More Information?

Log on to www.pumpefficiency.org or call the Program
using the following toll-free numbers:
Main Office/San Joaquin Valley - (800) 845-6038
Northern California - (866) 333-8938
Southern California - (866) 333-8939
Central Coast - (866) 473-0847
Please feel free to contact us if you have any questions.

How to Interpret a Pump Test Report

Run Number 1 of 1
1. Standing Water Level (ft):

43

2. Recovered Water Level (ft):

45

3. Draw Down (ft):

4. Pumping Water Level (ft):
5. Discharge Pressure at Gauge (psi):

5
48
20.3

6. Total Lift (ft):

95

7. Flow Velocity (ft/sec):

3.8

8. Measured Flow Rate (GPM):

440

9. Customer Flow Rate (GPM):

450

10. Well Specific Capacity (GPM/ft):

88

11. Acre-Feet per 24 Hours:

1.9

12. Cubic Feet per Second (CFS):

0.98

13. Horsepower Input to Motor:

23.1

14. Percent of Rated Motor Load:

104%

15. Kilowatt Input to Motor:

17.2

16. Kilowatt-Hours per Acre-Foot:

212

17. Cost to Pump an Acre-Foot:

18. Energy Cost ($/Hours):
19. Base Cost per kWh:

$22.26
$1.81
$0.105

20. Name Plate RPM:

1760

21. Measured RPM:

1755

22. Overall Plant Efficiency (%):

45.7%

The results section of an electric-powered pump test report

prepared by a participating pump test company of the
Program is shown above.
The following explanations can give you a better idea of what
is measured and calculated in a pump test:
1. Standing Water Level - The water level in the water well
when a pump has not been running.
2. Recovered Water Level - The water level in the water well
15 minutes after shutting the pump off.

3. Draw Down - The difference between the pumping

water level (line 4) and the standing water level (line 1).
4. Pumping Water Level - Where the water level in the well
stabilizes under constant pumping conditions.
5. Discharge Pressure at Gauge - The pressure on the outlet
side of the pump.
6. Total Lift - Includes the pumping water level, discharge
pressure, and any gauge corrections.
7. Flow Velocity - How fast the water is moving in the
discharge pipe. It should be 1 foot per second or faster
to ensure an accurate test.
8. Measured Flow Rate GPM - The flow rate measured
in gallons per minute using the tester's instruments.
9. Customer Flow Rate GPM - The flow rate measured
with the customer's flow meter (if one is present).
10. Well Specific Capacity - The measured flow rate divided
by the draw down (line 8 divided by line 3). It is a
measure of well performance, not pump performance.*
11. Acre-Feet per 24 Hours - The number of acre-feet
pumped in 24 hours at the measured flow rate. One
acre-foot of water is equal to 325,900 gallons of water.
12. Cubic Feet per Second - The measured flow rate
expressed as cubic feet of water per second.
13. Horsepower - The horsepower input to the motor read
at the utility meter.
14. Percent of Rated Motor Load - The estimated
horsepower output of the motor divided by the name
plate horsepower. If this is not between 80% and 115%
it is an indication that the motor is not matched to the
pumping condition.
15. Kilowatt Input to Motor - The power input to the motor
in terms of kilowatts. One horsepower is equal to 0.746
kilowatts.
16. Kilowatt-hours per Acre-Foot - The amount of
kilowatt-hours required to pump an acre-foot of water
at the operating condition measured.
17. Cost to Pump an Acre-Foot - Kilowatt-hours per acrefoot multiplied by the Base Cost per kWh (line 19).
18. Energy Cost ($/hour) - The cost per hour to run the
pump at the Base Cost per kWh (line 19).
19. Base Cost per kWh - The average cost of a kilowatt-hour
for this account.
20. Name Plate RPM - The rated speed of the motor.
21. Measured RPM - The actual rotational speed measured.
22. Overall Plant Efficiency - The power output of the
pump (a function of the flow rate and total lift) divided
by the input power.**
* see page 10
** see page 10

Assumptions

Pumping Cost Analysis

1.
2.
3.
4.
5.

6.
7.
8.
9.
10.
11.
12.
13.

Overall plant efficiency is improved to: 66.0%

Motor loaded at: 105%
Flow rate will be: 540 GPM
Total Head will be: 117 feet = 49 ft PWL, 29 psi discharge
Water requirements will be: 122.5 acre-ft/year
Existing Efficiency
kWh/AF:
213
Estimated Total kWh:
25,970
Average Cost per kWh:
$0.13
Average Cost per hour:
$3.00
Average Cost per Acre-Foot:
$28.04
Estimated Acre-Feet Per Year:
123
Overall Plant Efficiency:
45.7%
Estimated Total Annual Cost:
$3,449

IMPORTANT! The pumping cost analysis presented is only valid

for the assumptions listed in lines 1 - 5 and for the conditions
measured during the test. One or more of the assumed variables
resulting from a pump repair could be in error and the
economics presented would be misleading. Use this section only
as a guide to the magnitude of potential savings. Always consult
with your pump service company and other available experts
before making the decision to retrofit/repair a pump.
LINES 1 - 5:
Lines 1-5 list the important assumptions regarding the pump
performance after any retrofit or repair, including:
1. The improvement expected in Overall Plant Efficiency
2. Motor loading (this may be greater than 100% if it is
currently measured as greater than 100%)
3. Any change in Flow Rate
4. Any change in Total Lift
5. Annual water requirements will be assumed to be
unchanged
The software used by participating pump test companies
allows for any of these assumptions to be changed as needed.
You may want to dicusss these assumptions with the tester so
that they match your expectations (or the expectations of
your pump repair company).

Below is an example of the pumping cost analysis section of

an electric-powered pump test report prepared by a
participating pump test company of the Program.

(PWL = pumping water level)

Improved Efficiency
182
22,242
$0.13
$3.15
$24.98
123
66.0%
$3,073

Estimated Savings
31
3,728
$0.15
$3.06

$376

LINES 6 - 13:
Lines 6 - 13 are termed the "Before and After" section and lists
statistics based on the measured condition and the improved
condition assumed as a result of a retrofit/repair project.
6. kWh/AF - The kilowatt-hours required to pump an acrefoot through the system.
7. Estimated Total kWh - The total kilowatt-hours used
annually if the hours of operation or total acre-feet
pumped per year are known.
8. Average Cost per kWh - The average cost per kilowatthour as stated by you, or estimated by the tester based on
your pump size and rate schedule.
9. Average Cost per Hour - The average cost per hour to
run the pumping plant.
10. Average Cost per Acre-Foot - The average cost to pump
an acre-foot of water through the system.
11. Estimated Acre-Feet per Year - The estimated acre-feet
per year pumped through the system.
12. Overall Plant Efficiency - The overall pumping plant
efficiency (which may be zero in the case where the pumping
water level in a well cannot be measured for some reason).
13. Estimated Total Annual Cost of Energy - The estimated
annual cost of energy may not include demand charges
or other surcharges to run the pump. This will be zero if
the annual hours of operation or annual acre-feet
pumped are not known.
IMPORTANT! If the annual hours of operation or acre-feet
pumped are not known use line 10, the average cost per acrefoot, as an indicator of potential energy and dollar savings.

* Well specific capacity is a complex relationship based on

the aquifer conditions, well casing diameter, well screen,
gravel pack selection, and the initial development. For
example, high specific capacity wells in the San Joaquin
Valley have specific capacity greater than 100 gpm per foot
of draw down. Good wells are between 50 to 100 gpm per
foot. Low specific capacity of 5 to 20 gpm per foot may be
typical for your area or may indicate a problem. Well
performance will generally degrade with time. Well screens
can corrode or encrust with various deposits that reduce
flow openings into the well. Gravel packs can also
experience plugging from fine materials such as silt.
Attempting to pump too much water by using too big a
pump for the aquifer also results in low well specific
capacity. This subject is very important to your pumping
costs. Consult with your pump dealer and/or well driller if
the pump test history reveals significant reductions in well
specific capacity over time.
**Overall plant efficiency can be generally characterized as
follows:
60% and higher is excellent
50% to 60% is good
49% or less indicates a pump that may need a retrofit,
repair, or adjustment. It also may indicate the pump is not
matched to the current required operating conditions. An
example of this would be where a water table has dropped
substantially over time, increasing the total lift above the
original specifications.
Pumps with submersible motors will usually run about
10% lower efficiency in each of the categories above. For
example 50% or above would be considered excellent for a
submersible pump.
IMPORTANT! These are general characterizations. Always
consult with your pump service company and other available
experts before making the decision to retrofit/repair a pump.

The Center for Irrigation Technology

The Center for Irrigation Technology developed and
manages the statewide Agricultural Pumping Efficiency
Program. CIT is dedicated to advancing water/energy
management practices and efficient irrigation technology.
Located on the campus of California State University,
Fresno, CIT functions as an independent testing laboratory,
applied research facility and educational resource to both the
public and private sectors. For more information, check the
CIT link at www.pumpefficiency.org or call (800) 845-6038.

10

Important!
The Program may be terminated or modified without
notice. The Program has a limited budget. Applications
for retrofit/repair rebates or pump tests are accepted on a
first-come, first-served basis until available funds are
allocated or the ending date of the program, whichever
comes first (visit www.pumpefficiency.org or call
800.845.6038 for more information).
California consumers are not obligated to purchase any
full fee service or other service not funded by this
program. This program is funded by California utility
ratepayers under the auspices of the California Public
Utilities Commission.
Los consumidores en California no estan obligados a
comprar servicios completos o adicionales que no esten
cubiertos bajo este programa. Este programa esta
financiado por los usuarios de servicios pblicos en
California bajo la jurisdiccion de la Comisin de servicios
Pblicos de California.

11

Development and management of the

Agricultural Pumping Efficiency Program by:

The Center for Irrigation Technology

California State University, Fresno
5370 North Chestnut Ave. M/S OF 18
Fresno, CA 93740-8021
(559) 278-2066
APEP-04 1-04