Know the symptoms
Weak, short spray, rotors that stall or heads that barely rise point to low pressure or low flow. Heavy misting points the other way, to pressure that is too high.
Note whether the problem is in one zone or all of them.
One zone or all zones
If one zone is weak, look at that zone: a clog, a partly open valve, a leak or too many heads. If all zones are weak, look at the supply: a partly closed main valve, a clogged filter, a failing backflow device or a problem with the water supply.
This one question narrows the search a great deal.
Common causes
Clogged nozzles and screens, valves that do not open fully, leaks, crushed or undersized pipe, old galvanized pipe, a partly closed isolation valve and a stuck backflow device all reduce pressure.
Heads added to a zone without extra flow dilute the pressure at all of them.
Weak supply
Some properties have naturally low pressure or limited flow, especially at the end of a long supply line, at a high elevation or on a well. In those cases, zones must be smaller, or a booster pump is needed.
A pressure test at the connection shows what you have.
Pressure that is too high
High pressure turns spray to mist, wastes water and wears parts. A pressure regulator at the valve or pressure-regulating heads bring it to the right range.
Many heads work best at about thirty to fifty PSI.
Getting it fixed
A technician tests pressure at the supply and at the zone, checks each possible restriction and tells you the cause. Fixes range from cleaning a filter to adding a pump.
Our problem checker can help you describe the symptoms before you call.
Check whether one zone or all zones are weak, because that points to the cause.
