Your irrigation cycle ends, the sprinklers retract, and everything appears to shut down normally. A few minutes later, however, one sprinkler head is still trickling water into the lawn. In other cases, the leaking continues much longer and leaves a soggy patch around the head.
A sprinkler that releases water after the irrigation system shuts off does not always mean the sprinkler head itself is broken. The cause can be as simple as water draining from the pipes because of an elevation change, or it can point to a valve that is not closing completely.
Knowing the difference can help Georgia property owners determine whether they are seeing normal system drainage or an irrigation problem that needs attention.
Hearn Landscape provides irrigation installation and repair services for existing systems as well as new irrigation projects throughout its Georgia service area. The company specifically handles irrigation leaks, valve problems, pressure concerns, and system adjustments.
First, Pay Attention to How Long the Sprinkler Leaks
The amount of time the sprinkler continues releasing water provides one of the first clues.
If a sprinkler at the lowest part of the yard drips or flows for a short period and then stops completely, the system may simply be draining the water that remained inside the lateral irrigation line.
If the water continues for a long time, never completely stops, or appears every day even when that zone has not recently operated, there may be a different problem.
Also notice whether:
- Only one or two low sprinkler heads are leaking
- Several sprinklers throughout the same zone continue running
- Water is barely trickling or still spraying with pressure
- The wet area disappears after several minutes or remains saturated
- The problem occurs after every watering cycle
- The sprinkler leaks even when the controller has been off for hours
These details can help distinguish between low head drainage and a valve that is allowing water to continue entering the zone.
Low Head Drainage Is One of the Most Common Explanations
An irrigation zone contains water even after its control valve closes. If part of the zone is located downhill from another section, gravity can cause the remaining water inside the pipe to travel toward the lowest sprinkler head.
Rain Bird refers to this as low head drainage, which is residual water flowing from low elevation sprinklers after the control valve has already closed. The company explains that water remaining in irrigation lines naturally moves downhill and can eventually escape through the lowest sprinkler or emitter. (Rain Bird’s explanation of low head drainage)
This situation is especially noticeable in yards that have:
- Sloped lawns
- Retaining walls
- Elevated landscape beds
- Irrigation zones that run from high ground to lower ground
- Long lateral irrigation lines
- Sprinkler heads positioned at the bottom of a hill
The sprinkler may continue draining until enough water has left the pipe that gravity can no longer push it through the head.
How Can You Tell If It Is Just Drainage?
Low head drainage usually has a recognizable pattern.
The leaking tends to occur at the lowest sprinkler in the zone. It begins shortly after that zone stops running and eventually stops on its own.
For example, imagine an irrigation zone that waters a sloping front lawn. After the controller shuts the zone off, the sprinkler near the driveway at the bottom of the slope keeps releasing water while the sprinklers farther uphill remain dry.
That pattern strongly suggests that water already inside the pipe is draining downhill rather than new water continuously entering the irrigation zone.
The amount of drainage can vary depending on the length of pipe, the amount of elevation change, and how much water remains in the lateral line.
Why Repeated Low Head Drainage Is Still Worth Addressing
Even if the irrigation valve is functioning correctly, repeated drainage can create problems around the lowest sprinkler.
Water leaving the same head after every irrigation cycle may contribute to:
- Persistently soggy soil
- Puddling around the sprinkler
- Runoff onto a driveway or sidewalk
- Erosion on a slope
- Excess watering in one small section of lawn
- Soil settling around the sprinkler body
Rain Bird notes that check valves can be used to prevent water remaining in lateral lines from draining through low elevation sprinkler heads. Check valves hold water inside the line when the irrigation zone shuts off, reducing low head drainage and the associated pooling or erosion.
The correct solution depends on the system design and elevation differences, so the entire irrigation zone should be evaluated rather than simply replacing the sprinkler head.
A Valve That Does Not Close Completely Creates a Different Problem
If water keeps flowing long after the irrigation cycle ends, the control valve may not be sealing properly.
Irrigation valves are responsible for opening when the controller activates a zone and closing when that watering period ends. If the valve does not fully close, a small amount of pressurized water can continue entering the lateral line.
That water eventually has to go somewhere, and it commonly appears at one or more sprinkler heads.
Rain Bird’s valve troubleshooting guidance lists debris inside the valve or damage to the valve’s closing mechanism among potential reasons water may continue leaking from sprinkler heads while a station is supposed to be off. Another Rain Bird troubleshooting resource notes that debris or damage to the valve diaphragm can prevent a zone from shutting off correctly.
Why Dirt and Debris Can Affect an Irrigation Valve
Irrigation valves contain internal components that must create a reliable seal when the system shuts down.
Small particles of dirt, sand, mineral material, or other debris can sometimes prevent that seal from closing completely. Instead of shutting water off entirely, the valve allows a small amount of water to continue passing through.
The homeowner may never see the valve itself leaking because the unwanted water travels underground through the irrigation piping and emerges from a sprinkler farther away.
This is why replacing the visibly leaking sprinkler head does not always solve the problem. The head may simply be where the water is escaping. The actual problem could be located at the irrigation valve controlling the entire zone.
A Worn or Damaged Valve Diaphragm Can Cause Continuous Seepage
Inside many irrigation valves is a flexible diaphragm that helps regulate water flow.
Over time, the diaphragm can wear, become damaged, or fail to seat correctly. When that happens, the valve may not create a complete seal after the controller turns the zone off.
Hearn Landscape has previously discussed irrigation valve problems in its guide to how winter weather impacts irrigation valves. The company notes that aging diaphragms, seals, fittings, and other internal valve components can become sources of leakage and operational problems.
A valve problem becomes particularly likely when water continues flowing indefinitely instead of stopping after the remaining water in the line has drained.
The Sprinkler Head Itself Can Still Be Damaged
Not every irrigation leak comes from the valve.
Sprinkler heads are positioned at ground level, where they are exposed to lawn mowers, vehicles, foot traffic, soil movement, and landscaping work. The sprinkler body, nozzle, riser, or underground connection can become cracked or damaged.
Rain Bird identifies broken nozzles and damaged sprinkler heads as common causes of visible leaking while an irrigation zone is operating.
The timing matters, however.
A damaged head may leak excessively whenever water is supplied to the zone. Once the valve closes and the water in the pipe has drained, a broken sprinkler head by itself should not continue receiving pressurized water indefinitely.
If the head leaks continuously while the zone is supposed to be off, the technician may need to investigate both the head and the valve supplying that zone.
Watch for Soggy Areas That Never Fully Dry
Sometimes the first sign of an irrigation problem is not flowing water that you can see. It is one section of lawn that always seems wetter than everything around it.
Hearn Landscape notes that persistent soggy areas, unexpected water use, and pressure changes can be indicators of irrigation leaks. Its guide to preparing irrigation systems for summer also discusses how some lateral line leaks may remain underground and be difficult to identify from the surface.
Walk through the property several hours after the irrigation system has finished. Look for soil that remains unusually soft around sprinkler heads, valve boxes, and portions of the lawn.
A sprinkler that repeatedly leaks after shutdown may keep the immediate area wetter than the rest of the zone even if the amount of water appears small.
Why Irrigation Leaks Matter in Georgia Landscapes
A slow irrigation leak may not look urgent, but irrigation systems operate repeatedly throughout the growing season. A small problem occurring after every cycle can continually apply water where it is not needed.
The University of Georgia Cooperative Extension recommends inspecting irrigation systems for leaks, pressure problems, broken components, runoff, and other conditions that reduce irrigation efficiency. UGA also advises operating and maintaining sprinkler systems so that water is directed where it is needed rather than being lost through leaks or excessive runoff. (UGA water conservation guidance)
Excess water can be particularly noticeable in Georgia yards with dense clay soils because the soil may absorb water slowly. Repeated leakage in one location can leave the area wet even while other parts of the lawn need normal irrigation.
Do Not Simply Reduce the Irrigation Schedule to Compensate
If one sprinkler is leaking, shortening the zone’s watering time may seem like an easy solution. That approach can create a different problem.
The rest of the zone may then receive less water than intended while the leaking area remains wet.
The better approach is to identify why the sprinkler continues releasing water.
If the problem is low head drainage, the system design and possible use of check valves can be evaluated. If the valve is not sealing, the valve may need cleaning, adjustment, repair, or replacement. If the sprinkler itself is damaged, the head or its connection may need repair.
Correcting the cause allows the irrigation schedule to remain based on the actual needs of the landscape.
Could Landscape Changes Cause a New Drainage Problem?
An irrigation system that worked correctly for years can behave differently after major changes to the yard.
Projects such as:
- Regrading the lawn
- Installing retaining walls
- Adding landscape beds
- Replacing sod
- Building a patio
- Changing sprinkler locations
- Extending an irrigation zone
can alter elevation or how water moves through the irrigation system.
Hearn Landscape provides both grading and drainage services and irrigation work, which can be useful when the irrigation concern is connected to larger changes in the property.
If leaking began after a landscape renovation, let the irrigation technician know what changed.
What Should You Check Before Calling for Irrigation Repair?
You do not need to disassemble the valve or dig up the sprinkler system yourself. A few observations can make diagnosis easier.
Run the problem zone and watch what happens when it shuts off.
Note:
- Which sprinkler heads continue releasing water
- Whether those sprinklers are at the lowest part of the property
- How long the leaking continues
- Whether the water eventually stops completely
- Whether other heads in the zone also leak
- Whether the ground remains soggy between watering days
- Whether the problem occurs every time the zone operates
- Whether landscaping or grading work was recently completed
If possible, take a short video immediately after the zone shuts off and another several minutes later. That can help show whether the water is gradually draining or continuing at a consistent rate.
When Should a Sprinkler Leak Be Professionally Inspected?
A small amount of temporary drainage from a low sprinkler head may have a straightforward explanation. Professional inspection becomes more important when:
- Water never completely stops
- Several sprinkler heads continue leaking
- The area remains constantly saturated
- The zone appears to have pressure even while off
- The same problem returns after replacing a sprinkler head
- Water is running onto pavement
- Soil is eroding around the head
- The valve box remains unusually wet
- Other sprinklers in the zone have reduced pressure
- Water use has increased without a change in your irrigation schedule
UGA Extension encourages regular irrigation inspections because leaking or malfunctioning components can waste water and reduce system efficiency.
Find the Source Instead of Replacing Parts at Random
When a sprinkler continues leaking after shutdown, the sprinkler head is only the visible part of the system.
A short period of leaking at the bottom of a slope may be low head drainage caused by water remaining in the irrigation line. Continuous water can point toward a valve that is not completely closing. Damage to a sprinkler head, riser, valve diaphragm, or other component may create additional symptoms.
The key is determining where the unwanted water is coming from before deciding what needs to be repaired.
Hearn Landscape installs and repairs irrigation systems for lawns and landscaped properties throughout Georgia. If your sprinklers keep leaking after the controller shuts them off, the team can evaluate the heads, valves, zones, pressure, and system layout to determine what is causing the problem.
Visit Hearn Landscape’s irrigation installation and repair service to learn more or request service for an irrigation system that is not operating correctly.