Why hillside leaks are tricky
Water follows gravity and the easiest path through the ground. A leak on a main line high on a lot can show up as a wet patch near the bottom of the slope, seep out at the base of a retaining wall or vanish into a planter. Irrigation lines, which run under pressure through much of a yard, add more places for leaks to hide.
High house pressure makes leaks more likely and faster. On older homes, slab-on-grade construction adds another hidden location: supply lines running under the floor.
The meter test
This takes a few minutes and tells you whether water is going somewhere it should not.
- Stop all water use.Turn off faucets, appliances and the irrigation controller. Make sure no toilet is refilling.
- Find the leak indicator.Open the meter box and look for a small triangle, star or dial that spins with low flow.
- Watch it.If it moves with everything off, water is flowing somewhere.
- Close the house shutoff.If the indicator stops, the leak is inside the house or past the shutoff. If it keeps moving, suspect the line between the meter and the house, or irrigation tied in before the shutoff.
Where leaks show up and what it may mean
| What you notice | Possible source |
|---|---|
| Wet or green strip across the yard | Main water line between meter and house |
| Seepage at the base of a retaining wall | Line or irrigation uphill of the wall |
| Warm spot on a floor | Hot water line under the slab |
| Running sound with everything off | Toilet, supply line or a hidden pipe |
| Sudden bill increase | Any of the above, or a running toilet |
| Water around a sprinkler valve box | Irrigation valve or line |
How a leak search usually unfolds
- First
- Meter test and isolation using the house shutoff and irrigation valves.
- Next
- Pressure test of sections of piping to see which one loses pressure.
- Then
- Acoustic listening equipment or line tracing to narrow the location.
- Finally
- Targeted opening of soil, slab or wall to confirm and repair.
Repair the spot or reroute the line
Spot repair
- Fix the leak where it is found
- Less disruption if access is easy
- Sensible for a single failure on otherwise sound pipe
- Slab or deep slope access can make it hard
Reroute or replace
- Run a new line by an easier path
- Avoids breaking a slab or wall
- Better when the old line has repeated leaks
- Larger job; permits may apply, check with the city
Questions to ask
- Which section failed the pressure test?
- How confident are you in the location before opening anything?
- Is a spot repair or a reroute better for this pipe's age and material?
- How will the slope, walls and landscaping be restored?
- What is your CSLB license number?
Common questions
Is a soggy slope dangerous?
Saturated soil can affect slope stability and retaining walls. Shut off the water feeding the area if you can and have the source found promptly.
Could it be irrigation rather than plumbing?
Often it is. Turning the irrigation off at its own valve during the meter test helps separate the two.
Will the city fix a leak before the meter?
Leaks on the utility side of the meter are a question for Fullerton's water utility. Contact them if the leak appears to be there.
General information for Coyote Hills, not a quote or professional advice. In an emergency, call 911.