San Diego water, leak, drain and sewer diagnostics — find the source before anyone opens a wall.
WaterLine ExpertsRequest ServiceA line failing under concrete cannot be seen and does not have to be. It gives itself away through temperature, sound, pressure and the meter — usually weeks before anything appears on the floor.
Describe what you are seeingSlab-on-grade has been the standard foundation in San Diego since the tract building of the 1950s, which puts a substantial amount of supply pipe inside or beneath concrete with no crawlspace, no access panel and nothing to lift. A line in that position cannot be inspected, reached or even seen without opening the floor over it — which is what makes locating equipment central here rather than optional: without it, the alternative to finding the leak is not looking at the pipe, it is opening concrete speculatively until something turns up. The water itself contributes. San Diego's supply is hard — the city's own reporting puts total hardness in the region of 216 to 284 parts per million, roughly 12.6 to 16 grains per gallon, varying with the treatment plant and the seasonal blend of Colorado River and State Water Project water. Mineral-heavy water is the mechanism behind pinhole failures in copper that has been sound for decades: the pipe does not fail because something happened to it, it fails from the inside out, which is why a first slab leak on an older copper system is worth treating as information about the whole run. Age matters on top of that. A postwar home may still be on its original galvanised supply lines, which fail by internal corrosion along their length rather than at a single identifiable point — and a line failing that way tends to produce a second leak not long after the first. Ground that moves seasonally is a further contributor, because it puts stress on rigid pipe cast into or beneath a slab, and stressed pipe fails at whatever point was already weakest.
The signs of a slab leak are displaced from the leak itself, and understanding why is what stops a small repair becoming a large one. Water escaping under a slab enters the gravel or sand bed beneath the concrete, spreads laterally, and only rises where it finds a route — a control joint, a crack, the gap at the perimeter where the slab meets the wall, or the edge of a floor covering. It surfaces at the easiest exit, not the nearest one. Heat behaves differently, and that is useful. A hot-water line loses heat into the concrete directly above it, so a warm patch sits genuinely close to the pipe even when the visible water does not. Sound behaves differently again: concrete carries the noise of escaping water well, which is why acoustic equipment can pick out a peak directly over a failure through a solid floor. So the three most locatable signals — sound, heat, and a measurable loss of pressure — are all things the leak is doing right now, and none of them require anyone to see water. That is the entire reason a slab leak can be marked on a floor before a single tool touches the concrete.
Fits when: The location is confirmed, the rest of the line is sound, and the concrete above it is accessible without dismantling a kitchen.
Trade-off: Direct, and permanently fixes that failure. The cost sits in cutting, reinstating and refinishing the floor rather than in the pipe repair itself.
Fits when: The failure is under something expensive or impossible to open, or the buried run is old enough that opening it once is unlikely to be the last time.
Trade-off: No concrete is broken. It costs more pipe, runs the new line through walls or attic, and abandons the old section in place — which is standard practice, not a shortcut.
Fits when: A second or third failure on the same lines, or a pipe material that is corroding along its length rather than failing at a point.
Trade-off: The largest job and the only one that ends the sequence. Worth stating plainly when the evidence supports it, and worth arguing against when a single defect is all there is.
You can get most of the way. Turn off every fixture and the irrigation controller, then watch the meter for half an hour — movement means water is leaving the system. Then close the isolation valve at the water heater and watch again: if the movement stops, the loss is on the hot side, which is consistent with a warm floor. Neither test tells you where the leak is, but together they tell you what it is, and they cost nothing.
It runs continuously, so the damage accumulates continuously — into the soil under the slab, into the floor structure, and into whatever the water eventually reaches. The plumbing repair does not usually get harder with time, but the drying and reinstatement around it does, and that is commonly the larger half of the total. Waiting also gives soil under the slab time to wash out, which is its own problem.
No. Once the spot is confirmed there are generally two paths: open a small, specific area of concrete over it, or abandon the buried run and reroute a new line through walls or attic instead. Which one makes sense depends on where the leak sits, how the house is piped, and whether the rest of that line looks likely to fail next. Opening concrete before the location is known is what turns a small repair into a large one.
Opening a wall to inspect a riser or a visible connection is reasonable when it is targeted and explained. Opening several places hoping to find water is not, and it is worth asking directly: what has been ruled out so far, and what will this specific opening prove either way? Locating equipment exists so that the first cut is the last one.
A second failure changes the question from where this leak is to why this system keeps failing. If the two leaks are on the same material and the same age of pipe, a pattern is the most likely explanation and repiping is a legitimate answer to it. If they are on different systems — one hot, one cold, or one supply and one waste — that is weaker evidence, and worth resisting a full repipe on. The pipe condition should be assessed and shown to you, not asserted.
Not reliably. A standard inspection is visual, and a slab leak is by definition not visible — it is entirely possible for a line to be leaking under concrete throughout an inspection without a single sign in the rooms above. A meter check with everything off takes minutes and is worth asking for specifically, because it is the one test that would catch it.
A warm patch, a sound, a damp area, a bill, or the meter moving with everything off — whichever of those you have, and roughly when it started. If you have already isolated the water heater, that result narrows the search immediately.
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