Common Causes of Low Pressure

Leak in System

Underground pipe breaks or loose fittings stealing water from heads.

Clogged Nozzles/Filters

Debris blocking nozzle screens or inline filters.

Too Many Heads per Zone

Zone demands more GPM than supply can provide.

Partially Closed Valve

Main shut-off, backflow, or zone valve not fully open.

Home Water Use

Running water inside while irrigation operates.

Municipal Supply Issue

City water pressure low during peak hours.

Measuring water pressure

1 Measure Your Pressure

Use a pressure gauge on a hose bib to establish baseline pressure:

  • 40-80 PSI: Normal residential range
  • Below 40 PSI: Too low - may need booster pump
  • Above 80 PSI: Too high - install pressure regulator

Test with no other water running in the house, then test again while irrigation runs to see the drop.

Get a Pressure Gauge

Water pressure gauges at Lowe's cost under $15 and attach to any hose bib.

2 Check for Underground Leaks

Signs of a leak stealing pressure:

  • Soggy spots when system is off
  • Water bubbling when zone runs
  • One zone much weaker than others
  • Unusually high water bill

Walk the zone while it runs and look for water escaping from the ground. See our broken pipe repair guide if you find a leak.

Cleaning sprinkler nozzle filter

3 Clean Nozzles and Filters

  1. Lift the riser on each pop-up head
  2. Unscrew or pop off the nozzle
  3. Remove the filter screen (usually inside the nozzle or body)
  4. Rinse debris and reinstall

Dirt, sand, and mineral buildup can dramatically reduce flow. Clean filters at least once per season.

Shop Replacement Nozzles

Worn or damaged nozzles spray poorly even when clean. Replace with new ones from Lowe's.

Browse Nozzles

4 Check All Valves Are Fully Open

Verify these are 100% open:

  • Main water shut-off - at the meter or where water enters property
  • Backflow preventer valves - both handles should be parallel to pipe
  • Zone valve - solenoid and flow control fully open
  • Ball valves - handle parallel to pipe = open

Flow Control Adjustment

Many zone valves have a flow control screw on top. Turn it counter-clockwise until it stops to fully open. This is often overlooked!

5 Check Zone GPM Demand

If one zone is weak but others are fine, the zone may have too many heads for your water supply:

  1. Count all heads on the zone
  2. Look up each nozzle's GPM (usually stamped on nozzle)
  3. Add up total GPM demand
  4. Compare to your available GPM (from hose bib test)

If demand exceeds supply, you'll need to split the zone or use lower-GPM nozzles.

Solution: MP Rotator Nozzles

MP Rotator nozzles use 30% less water than standard sprays while providing better coverage. Great for overloaded zones. Shop MP Rotators at Lowe's

Advanced Solutions

Pressure Regulator Issues

If your home has a pressure regulator (usually near the main shut-off), it may be failing or set too low. Test pressure before and after the regulator.

Booster Pump

For chronically low municipal pressure, a booster pump can increase pressure to the irrigation system. This is a more advanced installation.

Pressure-Regulated Heads

If pressure varies wildly, consider heads with built-in pressure regulation. They maintain consistent output even when supply fluctuates.

Find Everything at Lowe's

Pressure gauges, replacement nozzles, filters, and more. Order online or visit your local store.

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