Why slab leaks are common here
A large share of the single-story tract homes built across Fullerton, Anaheim, Placentia, Buena Park and Yorba Linda in the 1950s through the 70s were poured as slab-on-grade foundations, with copper or galvanized water lines laid in the ground beneath. Those lines have now carried hard North OC water under pressure for decades.
Leaks start as pinholes where water velocity, minerals, soil contact or pipe rubbing against concrete or gravel wears the wall thin. Hot water lines tend to fail first, which is why a warm patch of floor is such a telling sign. Because the leak is under concrete, water can run into the soil for weeks before anything shows.
Signs of a slab leak
- The water meter moves when every fixture is off
- A warm or hot spot on tile, laminate or concrete
- The sound of running water with nothing on
- A water bill that rises without a change in use
- Damp or warped flooring, or carpet that stays damp at the edge
- The water heater running more than usual
- New cracks in flooring or mildew smell at floor level
Do your own meter test
- Turn everything off.Every faucet, the ice maker, irrigation, the washing machine and dishwasher.
- Read the meter.Open the meter box and watch the leak indicator, often a small triangle or dial, for a few minutes.
- Close the house shutoff.If the indicator still moves with the house valve closed, the leak is likely in the yard line between the meter and the house.
- Narrow it down.If it stops with the house valve closed, the leak is inside the house: a toilet, a fixture, or under the slab.
- Check toilets.Put a few drops of food coloring in each tank; color in the bowl without flushing means a flapper leak, not a slab leak.
Spot repair or reroute?
Spot repair through the slab
- Opens the floor directly over the leak
- Keeps the existing pipe route
- Flooring and concrete must be patched
- The rest of the under-slab pipe is the same age
Reroute through walls or attic
- Abandons the under-slab section
- Avoids breaking the floor
- Requires opening and patching drywall
- Removes that line from future slab-leak risk
How plumbers typically decide
| Situation | Common recommendation |
|---|---|
| First leak, pipe otherwise in fair shape, easy floor access | Spot repair is often reasonable |
| Second or third slab leak | Rerouting or a partial repipe is worth pricing |
| Leak under expensive tile or hardwood | A reroute may avoid costly flooring work |
| Galvanized or badly worn copper throughout | Whole-house repipe may make more sense than chasing leaks |
What drives the cost
- Locating the leak
- Detection is usually a separate step from the repair.
- Floor finish
- Tile, stone and hardwood cost more to open and restore.
- Route length
- Reroutes depend on how far the new line must run.
- Drywall and paint
- Patching after a reroute is often separate from the plumbing.
- Permits
- Repiping and reroutes may need a permit; check with the city.
Common questions
Is a slab leak an emergency?
A fast leak flooding the floor is, so close the main shutoff. A slow one still needs attention soon, since water under a slab can affect soil and flooring over time.
Can I keep using water?
If the leak is on the hot side, some homeowners close the cold supply to the water heater to stop it until the repair. Ask your plumber what is safe for your situation.
Will one slab leak lead to more?
Not necessarily, but the rest of the under-slab pipe is the same age and material. That is why repeat leaks often lead to a reroute or repipe.
General information for North Orange County, not a quote or professional advice. In an emergency, call 911.