San Diego water, leak, drain and sewer diagnostics — find the source before anyone opens a wall.
WaterLine ExpertsRequest ServiceA pipe under a foundation is not reachable and not visible, which is why the whole job is locating. Concrete gets opened once, over a spot that has already been confirmed twice — or not at all, if the line can be rerouted instead.
Tell us what the floor is doing
Two things about building and supplying homes in this region put more pipe at risk under concrete than a homeowner elsewhere would expect. The first is the foundation. Since the tract housing of the 1950s, slab-on-grade has been the standard way houses here are built: the structure sits on a poured pad, and supply lines serving the far side of the house commonly run within or beneath it. No crawlspace, no access panel, nothing to lift. That is the whole reason a failure in one of those lines is a detection problem rather than a plumbing one, and it is why slab leaks turn up far more often here than in regions that build over crawlspaces or basements. The second is what runs through the pipe. San Diego's supply is hard — the city's own reporting puts total hardness in the region of 216 to 284 ppm, roughly 12.6 to 16 grains per gallon, moving with the treatment plant and with the seasonal blend of Colorado River and State Water Project water. Mineral-rich water works on copper slowly and from the inside, and it is a large part of why a copper line that behaved perfectly for decades develops a pinhole rather than failing at an obvious weak point. It also explains why a first leak is a reasonable prompt to ask about the condition of the rest of the run rather than only about this one hole. Housing age adds a third variable. A post-tension slab and a conventionally reinforced slab are not opened the same way, and postwar homes may still be on their original galvanised supply, which fails by corrosion along its length rather than at a single point. Those distinctions change the answer to "repair or reroute" before anyone has looked at a joint, which is why the pipe gets assessed rather than assumed.
Hears pressurised water escaping through a small opening, conducted up through concrete. Strong on supply lines. Completely deaf to a drain or sewer line under the same slab, because those are not pressurised and make no continuous escape noise.
Reads surface temperature, so it traces a hot-water leak as a warm track across the floor. It sees heat and not water, which makes it excellent for confirming a hot-side location and close to useless on a cold-side one.
Establishes which section is losing water and roughly how fast. It costs nothing but time and removes whole zones from consideration, which is why it happens before any instrument comes out of the van.
Maps where the buried line actually runs and at what depth. This matters twice: it stops a search happening over the wrong part of the floor, and it is what a reroute gets planned against.
An inert gas introduced into a drained line escapes at the failure and rises through the slab, where a sensitive detector picks it up. Useful where noise conditions defeat acoustics — a very small leak, a very deep line, or a house that cannot be made quiet.
Map how far water has already travelled through flooring and wall material. That defines the drying job, not the leak location. The wettest reading is regularly nowhere near the failure.
Fits when: There is a practical path for a new line through walls, attic, or overhead, and the buried section has no reason to be preserved.
Trade-off: The floor stays intact. It costs more pipe and more labour above ground, and leaves the old run abandoned in place — which is normal practice and not a problem in itself. It is also the option that removes this particular length of pipe from ever failing again.
Fits when: The leak is near an edge or in an area where the floor covering is straightforward to reinstate, and the rest of the line is in sound condition.
Trade-off: Direct, and the pipe gets repaired where it is. The cost sits in the concrete work and the making-good rather than in the plumbing, and the floor finish above rarely comes back invisibly.
Fits when: The failure is under something that genuinely cannot be cut — certain post-tension slabs, or a floor finish that cannot be reinstated — and access from outside is possible.
Trade-off: Leaves the floor untouched and moves all of the work into excavation. It is the most involved access route and is chosen when the alternatives have been ruled out, not as an opening position.
Fits when: A second or third failure on the same system, or a pipe material that is failing by age along its length rather than at one accidental point.
Trade-off: The largest job, and the only one that ends the pattern rather than resetting it. Worth raising honestly when the failures are clustering, and worth arguing against when a single defect explains everything seen so far.
A leak that proves itself hot-side in ten minutes is a much shorter search than one that could be on the cold side, the hot side, or the irrigation feed.
Bare concrete, carpet, engineered timber, and set tile are four different reinstatement problems for the same length of pipe underneath.
A post-tension slab constrains where and how it can be opened, which frequently pushes the sensible answer toward a reroute regardless of what the leak itself would have cost to reach.
A deeper line takes longer to hear and longer to reach, and a run that does not follow the assumed route lengthens both halves of the job.
This is the repair-versus-repipe question, and it is settled by looking at the pipe condition rather than by counting how many leaks have happened so far.
Drying, and making good what got wet, is regularly the larger half of the total. It grows every day the leak is left running, which is the one part of the cost the homeowner controls.
How to tell a hidden leak from a usage change, using the meter you already have.
A step-by-step, no-tools-needed sequence for narrowing down a suspected leak before anyone visits.
Why the repair method decides the number more than the leak itself does.
The signs that point under the concrete, and the ones that only look like they do.
Why the wet spot is almost never where the water got in, and what to do about it first.
Slab leaks track slab-on-grade construction and hard water together, which is most of the county — San Diego's older urban core, Escondido's wide range of housing ages, and Carlsbad's older village pocket each show the pattern for slightly different reasons.
No. Finding it happens through the slab — acoustic equipment hears the escaping water, thermal imaging traces the warm path of a hot-side leak, and line tracing confirms where the pipe runs. Concrete only gets opened as part of a repair, over a spot that has already been confirmed. Anyone opening the floor in order to find the leak has the sequence backwards.
It is not usually a same-hour emergency, but it does not stabilise either. It runs continuously, the water spreads further into flooring and wall material every day, and the drying and repair bill grows with it while the plumbing part stays the same size. If the loss is severe, isolating the affected side at the heater or the main is a reasonable temporary measure while a decision gets made.
Concrete does not mind being wet. What can matter is the soil beneath it — water moving through supporting ground over a long period can wash out fines or change how the soil behaves, and that is a structural question rather than a plumbing one. It is a reason not to leave a known leak running for months, not a reason to panic about one found this week.
It is one of the stronger single indicators, but it is not proof on its own. A hot supply line running close to the surface, or hydronic heating, will also warm a patch of floor. What separates them is behaviour: a leak keeps the area warm continuously and usually comes with a second sign — a moving meter, a climbing bill, or a running-water sound with the house quiet.
Because reaching the leak is often the expensive part, and because a rerouted line puts the pipe somewhere reachable for the rest of its life. Where the buried section is old, or a second failure is plausible, spending the money on new accessible pipe is frequently better value than spending it on concrete work to reach one joint. Where the pipe is sound and access is easy, the opposite is true.
Where the leak was located, by what method, what the damage looked like when it was found, and the date. Photograph it before anything is opened up, because most of that evidence stops existing the moment work starts. It is what makes a real second opinion possible, and it is what any claim you make later will ask you for.
Then we say so, and tell you what has been eliminated and what going further would involve, rather than opening something speculative to be seen making progress. A confirmed "not on the hot side, not under this room" is a real result and it makes the next step cheaper.
The warm spot, the sound, the bill, or the damp — what you noticed, in which room, and roughly when it started. If you have watched the meter with everything off, tell us what it did. That single detail changes where the search begins.
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