Irrigation & sprinkler leak detection in Brisbane, CA
A sprinkler system can lose water for weeks without anyone seeing it, because it runs on a timer and often while you’re asleep. Finding where landscape water is escaping usually means working through the controller schedule, each zone, the valves and the buried lines feeding them. Call Brisbane Leakmark to ask whether irrigation leak investigation is available for properties in Brisbane and the nearby communities shown on our service areas page.
Describe the patch of yard that won’t dry out and roughly when it started.
Call (415) 532-1415What does irrigation leak detection check?
An irrigation system may branch from the building water supply or use a separate irrigation meter. A typical setup may include:
Backflow assembly
A device that keeps landscape water from flowing back into drinking water
Irrigation mainline
Pipe feeding the zone valves; it may remain pressurized between cycles unless a master valve shuts it off
Solenoid valves
Electrically opened valves, one per zone, usually in a valve box
Lateral pipes
Lines from a zone valve to the heads; normally pressurized during that zone’s run, but a leaking valve can feed them between cycles
Emitters
Spray heads, rotors, bubblers or drip tubing
The building’s supply line sits outside this scope. When the loss is on that line, see underground water line leak detection.
Why can sprinkler leaks be hard to notice?
Some controllers water before dawn, so a broken lateral can soak a planting bed while no one is watching. Drip tubing may be hidden under mulch, allowing a split tube or displaced emitter to go unnoticed. The first clue is often a bill rather than a puddle.
Why does a wet spot stay after sprinklers stop?
Where and when the soil stays wet narrows which part of the system to suspect.
| What you see | Possible source | Why it may fit |
|---|---|---|
| One soggy spot that never dries, even on non-watering days | Mainline, a weeping zone valve, or another water source | A mainline can stay pressurized; a master valve may shut it off between cycles |
| A wet line along a bed edge after one zone runs | Lateral pipe on that zone | Laterals are normally supplied during the zone cycle, but can drain afterward |
| Water bubbling around one head after watering stops | Low-head drainage or a cracked fitting | Water in the lateral drains out at the lowest head |
| Constant trickle at the lowest head in a zone | Weeping valve or residual low-head drainage | Check whether trickling stops after the line empties |
| Wet valve box | Valve body, connection, or water entering from nearby soil | Inspect without adjusting the assembly |
Can low sprinkler pressure indicate a leak?
- One zone sprays weakly, others are fine: likely a break or large leak on that zone’s lateral, or a partly closed valve
- Every zone is weak: a problem upstream, such as a mainline leak, the backflow assembly or low supply pressure
- Heads pop up but don’t rotate or reach: often clogged nozzles or worn heads rather than a leak
Poor coverage alone doesn’t prove a leak.
Valve boxes, controllers and backflow boundaries
Knowing what each part does helps you describe the problem and tells you who should touch it.
| Component | What tends to fail | What you’d notice | Who usually works on it |
|---|---|---|---|
| Controller (timer) | Wrong schedule, extra start times, a stuck station | Watering at odd times or for too long | Owner or irrigation technician |
| Solenoid valve | Torn diaphragm, debris in the seat, failed solenoid | Zone won’t shut off, or weeps between cycles | Irrigation technician |
| Backflow assembly | Worn internal parts, freeze or impact damage | Water dripping or spraying at the device | Certified backflow tester |
| Mainline | Cracks or failed connections | Wet ground between cycles where the line remains pressurized | Qualified irrigation or plumbing provider |
| Lateral and heads | Broken fittings, cut lines, worn seals | Wet only during or right after a cycle | Irrigation technician |
The City’s Public Works FAQ requires a yearly inspection of private backflow preventers, reported to the county’s cross-connection program.
Leaking drip systems versus spray heads
| Drip system | Spray or rotor heads | |
|---|---|---|
| How leaks show | Soft, saturated soil under mulch, or plants that suddenly thrive or rot | Visible puddles, erosion, misting or a geyser |
| Common faults | Split tubing, popped emitters, chewed lines, missing end caps | Broken nozzles, cracked risers, worn wiper seals |
| How easy to find | Harder, because tubing is covered and spread out | Easier, because faults appear when the zone runs |
| Pressure clue | Drip zones run at low pressure through a regulator, so leaks may not change pressure much | A break usually drops pressure along the zone |
Is the water loss indoors or outside?
First identify whether irrigation uses the household meter, a dedicated meter, or a shared supply. If the same meter serves the irrigation branch and the building, comparing readings with the irrigation isolation valve open and closed may help narrow the loss. Never operate a utility-owned meter valve. Our meter check guide walks through reading the meter, and underground leak vs irrigation leak explains how the two outdoor systems differ.
How to gather controller schedule evidence
- Photograph the controller screen for each program, including start times, run times and watering days.
- Note any rain or seasonal adjustment setting.
- List each station and what area it waters, if you know.
- Record when the wet spot appears relative to the schedule: during, just after, or all the time.
- Check for a master valve. Some systems have one that closes the mainline between cycles, and it changes how leaks behave.
Visual checks without digging
- Walk each bed and lawn area during a manual run of each zone
- Look for heads that spray sideways, mist, or don’t pop up
- Lift valve box lids only if they open easily, and look for standing water
- Check the backflow device for drips, without adjusting it
- Note erosion channels, sunken soil or unusually green patches
Don’t dig near the wet spot. Buried irrigation often shares ground with electrical, gas or communication lines.
Zone-by-zone testing principles
A systematic investigation tests one zone at a time and records what changes. A professional investigation follows this logic:
- Identify all meters, master valves and branch connections; compare readings with the irrigation branch isolated and restored where safe.
- Check whether the mainline remains pressurized while all zones are off; a master valve can change this pattern.
- Run zones one at a time and watch for pressure loss and new wet areas.
- Narrow a suspect zone to a section of lateral or a specific valve.
- Confirm with access only where the evidence points.
Even a partial log of what you’ve observed per zone helps when you call.
Valve leakage and stuck-open scenarios
| Scenario | What happens | Typical clue |
|---|---|---|
| Valve stuck fully open | The zone runs nonstop until the system is shut off | Heads keep spraying after the cycle ends |
| Valve weeping (not fully closed) | A small flow keeps entering the lateral | Constant trickle or wet ground at the lowest head |
| Valve body or connection leak | Water escapes at the valve itself | Water in the valve box |
| Controller fault | The valve is told to open when it shouldn’t | Watering at unexpected times |
Buried irrigation line investigation
Where suitable equipment and access are available, investigation may include pressure observation on an isolated section, tracing the line’s route, and listening methods where conditions suit them. Irrigation pipe is usually shallow plastic, which carries leak sound poorly, so acoustic results can be limited. The outcome is often a probable section rather than an exact point.
Landscape moisture versus storm runoff
- After rain, water collects at low points and the base of slopes, then dries over several dry days
- Downspouts and yard drains can pool water near the house during storms
- Overwatering keeps soil soggy without any leak, especially in shade or clay soil
- Runoff onto paths or the street during a normal cycle usually means a schedule or head-aim problem, not a break
Wet only after storms? An irrigation test won’t explain it.
Accessibility under planting and hardscape
Irrigation lines often run under mature shrubs, through planter walls and beneath paths. Confirming a leak may mean cutting through roots, lifting pavers or opening a section of lawn. Ask before any access how much will be disturbed and who restores it. Landscape restoration is not part of a leak investigation unless that work is included in the agreed scope.
When irrigation work differs from plumbing
Irrigation and building plumbing overlap at the point where landscape water branches off the supply. Beyond the backflow assembly, the work is usually done by irrigation or landscape contractors. On the building side, plumbers handle it. Backflow testing typically requires a certified tester. A single provider may not cover all three, so it’s worth asking which parts a provider actually handles.
Repair options after locating the fault
Once the fault is found, fixes range from replacing a nozzle or valve diaphragm to repairing a lateral or rerouting a section of mainline. Repair is a separate decision and may involve separate work—see irrigation and sprinkler leak repair for those choices.
Conserving water while awaiting diagnosis
- Turn the controller to “off” or close the irrigation system valve if you can find and reach it
- Hand-water stressed plants only as needed
- Use the City’s Water Calculator to reset the controller schedule once the system is fixed
- If you’re redesigning the yard, see BAWSCA’s free landscape classes and Lawn Be Gone! rebate
Brisbane watering and property context
California’s AB 1572 bans using drinking water on non-functional turf—decorative lawn not used for recreation. Per the City of Brisbane, the ban reaches commercial, industrial and institutional sites in 2028 and HOA common areas a year later. It does not apply to single-family residential yards. Commercial and large landscape accounts can check recommended water budgets through Waterfluence. For questions about water rules, the City lists its Water Department at (415) 508-2154.
What a complete irrigation evaluation may include
- Confirmation that the loss is on the irrigation side
- A zone-by-zone result: normal, leaking, weeping valve or stuck valve
- The suspected section and how confident the finding is
- Any parts that were not tested and why
- Whether the findings come in writing — confirm before the visit
Irrigation leak FAQs
Why is my yard wet when sprinklers are off?
A wet spot between watering cycles may come from a pressurized mainline, a valve that is not sealing, a nearby domestic supply line, or non-plumbing runoff. A master valve can make the mainline intermittent. Shutting off the irrigation system valve and watching the meter helps tell these apart.
Can irrigation leaks increase a home water bill?
Yes. Irrigation often runs for long periods several times a week, so a broken lateral or stuck valve can add a lot of water before anyone notices. Compare your bill with the same period last year to rule out a normal seasonal rise.
How do I know if a sprinkler valve is stuck open?
The zone keeps running after the controller ends its cycle, or water keeps trickling from the lowest heads long after watering. Turning the controller off won’t stop a mechanically stuck valve. Closing the irrigation system valve will.
Can the meter help isolate irrigation usage?
Sometimes. First check whether irrigation and the building use the same meter. If so, comparing readings with a safely accessible irrigation isolation valve open and closed may help. Neither result alone pinpoints a leak.
Do you test underground drip lines?
Only if the agreed scope includes drip systems. Drip faults are often found by running the zone and looking for saturated soil, popped emitters or split tubing under mulch. Ask on the call whether drip evaluation is available for your property.
Does irrigation leak detection include sprinkler repairs?
Not automatically. Detection identifies the faulty zone, valve or section; repair involves a separate decision about scope and access. Ask what repair steps, if any, can be arranged for your property.
How is irrigation leakage different from a broken service line?
A building service line generally carries water under pressure, while irrigation laterals normally receive water when their zones run. A master valve, separate meter, stuck valve or intermittent leak can blur this pattern.
Should I run each zone before calling?
Only if safe and without worsening flooding: run each zone for a brief observation, stop if a large leak appears, and note wet spots, weak spray or broken heads. It shortens the investigation and helps decide whether the visit should focus on irrigation at all.
Call about unexplained landscape water loss
A wet planting bed, a zone that does not shut off or unexpected water use can justify checking the irrigation layout and controller schedule before selecting a test.
Call (415) 532-1415