Do It Yourself, Water-wise Sprinkler Systems, Ft. Collins, CO and Northern Front Range

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The High Cost of Water Pressure

Correct water pressure is essential for efficient water distribution.

Irrigation equipment manufacturer's conduct extensive hydraulic performance tests to determine the most efficient operating pressures for turf spray heads and rotors. As a result of these tests, manufacturers compile "Nozzle Performance Charts."
www.hunterindustries.com/Products/Sprays/adjarcintro.html www.hunterindustries.com/Products/Rotors/i20data.html

Failure to follow manufacturer's operating pressure results in increased water use with decreased usable precipitation.

Most residential spray heads distribute water most efficiently at an operating pressure of 30 p.s.i. at the head. Most residential rotors distribute water most efficiently at 40 or 50 p.s.i. at the head.

Simply adjusting sprinkler system operating pressure to the manufacturerês recommended operating pressure can result in up to a 59% reduction in landscape water use.

A Front Range Problem
Because many Front Range water systems are gravity-fed from reservoirs in the mountains, many Front Range communities have extremely high water pressures. In 2005, Component Systems collected irrigation system water pressure data from 704 sprinkler systems in the Fort Collins area. The pressure readings were all taken immediately downstream of the backflow prevention assembly, which is the point at which water enters the sprinkler mainline.

Fifty-five percent of the systems surveyed had pressures at or above 80 p.s.i., which is too high or both household and irrigation use. Forty-one percent of the systems had pressures between 50 and 79 p.s.i., which is acceptable for household use, but too high for efficient turf spray head operation. Only three percent of the systems had pressures below 50 p.s.i., but over 35 p.s.i., which is, in most cases, too high for the most efficient turf spray head operation.

Excessive water pressure results in:

Heads produce mist instead of spraying large droplets
Significant water is lost to evaporation and wind
Water use (flow) increases
Usable precipitation decreases

Impact on your Water Bill
As the table below indicates, if a system uses 15,900 gallons per month at 75 p.s.i., reducing the pressure to 30 p.s.i. could reduce water use by 5,900 gallons per month.

Adjusting sprinkler system operating pressure from 75 p.s.i. to the manufacturerês recommended operating pressure can result in up to a 59% reduction in landscape water use.

To learn more about calculating water saving through pressure reduction go to Rain Bird Irrigation's page "5 Easy Steps to Cost Savings."

To learn how to adjust sprinkler system operating pressure go to "How to Adjust Water Pressure" (pdf).

Summary of Pressure Reduction Benefits

Lower water costs    Operating your sprinkler system at manufacturerês recommended pressure can reduce landscape water use by up to 59%. Because many water suppliers use tiered water rates, the cost savings may be greater than the water use savings.

Reduce watering time requirement    Because a significantly greater amount of the water used actually reaches the grass with correct water pressure, watering times can be reduced. This is especially important if your water supplier restricts the total amount of time you can water each week.

Reduce or Eliminate Water Hammer    "Water hammer" is the loud banging of pipes that many homeowners hear when their sprinkler system starts or stops. Pressure regulation, combined with heads with built-in check valves, can reduce or eliminate water hammer from the sprinkler system.

Benefits Inside the House    EPA research suggests that a reduction of household water pressure from 100 p.s.i. to 50 p.s.i. can result in a water flow reduction of about one-third. Reduction in water pressure can reduce the likelihood of leaking water pipes, leaking fittings, dripping faucets, damage to water heaters, and burst washing machine hoses. www.epa.gov/OW/you/chap3.html

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