Where copper sits in these homes
In many boom-era houses in the Las Vegas Valley, copper carries water from the meter, through the slab and up into walls to fixtures. A typical layout runs a loop or branches from the water heater, with lines that cross under rooms before they rise.
Copper is rigid, handles heat well and joins with soldered or brazed fittings. It has been installed in houses for generations. Under a slab, it lies in a trench, usually bedded in sand or gravel, and the concrete goes over it.
What a house actually has is confirmed on site. Build year suggests, but does not prove. Some houses have copper in part and other material elsewhere, because of a past repair or a repipe.
How copper under a slab leaks
Leaks in copper tend to be small. A pinhole, no bigger than a pin, can lose water continuously. A joint that has opened slightly can seep. A pipe that has worn against concrete or a footing can develop a pinch.
Causes vary. Water chemistry, flow speed, temperature, joint quality and what the pipe touches all contribute. In the Valley, hard water and hot-line heat cycles come up often. See hard water and copper leaks.
Copper in good condition can last for many years. What the technician sees at the leak helps indicate the condition of the rest.
Signs it is copper and under the slab
The signs are the same for any slab leak, but small copper leaks often start with a gentle version of each.
- A bill that creeps up over two or three cycles.
- A heater that runs more often than before.
- A faint hiss that you notice at night.
- A warm patch that is hard to feel at first.
- A meter that moves very slowly with everything off.
A slow meter movement is the clearest guide. The water meter check is a good first step.
How a copper leak is located
Copper carries sound well, which helps. An acoustic microphone moved along the floor above a line picks up the hiss of a leak. The signal is clearest near the break.
Isolation tells the crew which line. Pressure testing tells which branch. Thermal imaging adds a map on hot lines.
Some crews also use a line tracer to follow the route of the copper, since plumbing under a slab does not follow room edges. Knowing where the line runs helps place the mark.
The mark is checked from more than one direction before cutting. Slab leak detection covers the visit.
What the technician sees when the pipe is exposed
When the floor is open and the pipe is clear, the technician looks at three things: the leak itself, the pipe around it and the soil around the pipe.
A single pinhole in an otherwise clean pipe is one conversation. Several pinholes, a thin wall or green deposits along a stretch is another. The technician reports what is visible, and you can ask to see it.
They will also say what kind of fitting or joint is involved. A leak at a joint is different from a leak mid-run, and the repair differs.
This is often the first time anyone knows for certain what the pipe is and how it looks. It is worth asking questions.
Spot repair on copper
A spot repair replaces the damaged section. The technician cuts out the bad length and joins in a new piece with fittings. The line is tested before the opening is closed.
It suits a first leak, in an open area, with pipe that looks sound on either side. The disruption is concentrated in one place.
It is not a statement about the rest of the line. The technician may tell you honestly if the pipe looks worn nearby, and that conversation shapes whether a spot repair is what you choose. Slab leak spot repair covers the details.
Reroute and repipe for copper
If the line is worn, or if this is a second or third leak, rerouting is often suggested. The old line under the slab is capped and abandoned, and new line is run through walls or the attic. Many Valley homes have accessible attics, which makes this practical. Slab leak reroute has more.
A partial repipe replaces a group of lines. A whole-home repipe replaces most or all of them. These come up after several leaks, or where the technician finds widespread wear.
Lining as an option
In some cases, the technician may discuss lining: cleaning the inside of the pipe and applying a coating. It depends on the pipe, the condition and the leak. It is not suited to every line, and not every crew offers it. See pipe lining for slab leaks.
It is presented as one option among others, never as the default.
After a copper repair
The new section or line is pressure tested and the meter is checked. Over the next few days, check the meter with everything off. It should be still.
If another leak appears, tell the crew. Repeat slab leaks explains the conversation. Keep notes on where leaks occurred.
After the repair covers closing the opening and hand-off to flooring trades.
Joints, fittings and where copper leaks first
Copper pipe is joined with fittings: elbows at turns, tees at branches and couplings where lengths meet. Under a slab, these are made by soldering or brazing, which fuses the fitting to the pipe with a metal filler.
A well-made joint is strong and lasts. A joint that was not fully heated, or that had a gap, may have a weak point that opens years later. Flux left inside a pipe can also wear on the metal over time.
Joints are therefore common places for leaks, even though they are a small fraction of the line. A technician who opens the floor at a leak will look closely at the nearest fitting.
Elbows and tees are also places where water changes direction, which can raise wear on the inside surface, particularly if the flow is fast. That is one reason leaks sometimes appear at bends.
Along straight runs, a leak is more likely to be a pinhole, where the pipe wall has thinned from inside or been worn from outside.
Where a pipe passes through or beside concrete, such as at a footing or a slab edge, it can rub as the slab and pipe expand and contract at different rates. A sleeve is meant to protect it, and a missing or displaced sleeve can lead to wear.
All of this is general. When the pipe is exposed, the technician sees the actual cause: a joint, a pinhole, a rubbed spot. That tells you more than any list of causes.
Ask what the technician saw, and ask to see it. A photo of the leak and the pipe is a good record, and it helps if the same line is ever discussed again.
The information also guides the repair. A failed joint can often be replaced with a short section and two new joints. A thinned wall along a length may point toward a longer replacement or a reroute.
Questions to ask about a copper leak
- Was the leak at a joint, a bend or along a straight run?
- How did the pipe look on either side?
- Was there any sign of rubbing or wear from outside?
- How many other joints sit under the same stretch of floor?
- Would you replace a longer section, and why or why not?
- What does the quote cover for each option?
These questions help you understand what the technician is basing the recommendation on. The answers are not a promise of anything, but they tell you what was seen.
If you hear that the whole line is bad, ask what was seen to conclude that. If you hear that the rest looks fine, ask the same.
A clear, specific answer is a good sign. A vague one is a prompt to ask again.
Where this comes up in Nevada
Older copper is most common in older tracts, which is where wear shows first. Local pages that cover the homes and conditions around this topic include Sunrise Manor, Paradise, Central Las Vegas and Sun Valley.
The pages describe how older lines turn up in each area. The areas page has the full list.
Common questions
Is copper a bad pipe?
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No. It is a long-used material that serves many homes. Like any pipe, it can leak, especially at joints or where it has worn.
How do I know my pipe is copper?
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You cannot tell reliably from the build year. The technician confirms on site.
Why did it leak in just one spot?
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A pinhole usually starts where the wall is thinnest or at a joint. The technician examines the pipe around it.
Does one pinhole mean more are coming?
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Not always. The technician looks at the pipe to judge.
Can copper be repaired in place?
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Yes, a section can be cut out and replaced.
What causes pinholes?
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Water chemistry, flow, temperature and joint quality can all contribute. The cause varies by home.
Is copper safe to drink from?
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This site does not address drinking water. That is outside a slab leak visit.
Will the repair match the rest of the line?
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The technician uses appropriate materials and explains what goes in.
Related reading: slab leak repair.