Hard water and copper slab leak services in Nevada: why old lines start to leak

The context: copper under a slab

Copper has been a standard material for water lines in American homes for a long time, and it is common under the slabs of Las Vegas Valley houses built from the 1980s through the 2000s. It is durable, it handles heat and it has a good track record.

Under a slab, the line sits in a trench, usually packed with sand or gravel, then covered in concrete. It is out of sight and mostly out of mind. It does not get inspected, and it is exposed to what the water carries and what the ground contains.

This page makes no claim about any particular home. What is under your floor is confirmed on site, not assumed from the build year or the tract. What follows is a general account of why copper lines in hard-water areas can wear, and why technicians in the Valley see a certain pattern.

What hard water does

Hard water carries dissolved minerals. When the water is heated or sits in a line, some of those minerals come out of solution and settle on surfaces. Inside a pipe, they can form scale: a layer of deposit on the inner wall.

Scale builds slowly. It can narrow the bore, change how water moves, and in some cases trap tiny pockets where wear is concentrated. It is more pronounced on hot lines, because heat encourages the minerals to come out of the water.

It does not mean every line in a hard-water area is damaged. It means that in homes with decades of service, the inside of the pipe may no longer be smooth, and the wall may have thinned in places. This site does not give hardness figures or name any water provider, and it does not recommend any treatment equipment.

How copper wears

Copper can wear in a few ways, which technicians describe in general terms. Pinhole leaks are small holes in the pipe wall, often where the wall has thinned from the inside. Erosion happens when water moves quickly past a fitting or a bend and wears the wall. Pitting is a localised loss of wall that can eventually break through.

Several things influence the rate: the chemistry of the water, the flow speed, the temperature, the quality of the original joints and the surroundings of the pipe. Hot lines tend to wear faster than cold, and sections near the water heater are often the first to show it.

The line sits in contact with sand or gravel under the slab. Soil and fill can also play a role, which is one reason why different parts of a house, and different houses on the same street, can have different outcomes.

The pattern technicians see in Valley homes

In boom-era Las Vegas Valley homes, a first leak often appears on the hot side, in a small spot, and it is slow. The homeowner notices a bill that has crept up, or a warm patch. A spot repair fixes that point.

Months or years later, a second leak may appear on the same line, a few feet away or at another fitting. The line has worn in several places, not just one. This is where the conversation moves to rerouting or repiping.

This is a pattern, not a rule. Some homes have one leak and never another. Some have none. The technician looks at the leak location, the condition of the exposed pipe, the number of previous leaks and the layout of the house before suggesting anything.

Signs to watch for

A copper leak under the slab shows the same signs as any other: a warm spot, the sound of water, a heater that runs often, a rising bill and a meter that moves with everything off.

• A warm patch on the floor. See warm spot on the floor.
• A hiss or trickle when the house is quiet. See sound of running water.
• A bill that keeps climbing. See high water bill, hidden leak.
• A meter that moves with everything off. See the water meter check.
• A previous leak in the same house.

Pinhole leaks are slow, so signs can be subtle. A meter test is the most dependable way to confirm.

How the leak is confirmed

The technician starts with isolation: the hot and cold lines are separated and pressure tested one at a time. If one holds pressure and the other drops, the leaking line is known. Branches are tested in turn.

Acoustic locating then listens along the leaking line for the sound of the leak, and thermal tools map heat if it is a hot line. A mark goes on the floor.

If the floor is opened, the technician can see the pipe. At that moment, the material and its condition are confirmed, and the technician can say what they see. It is usually the first time anyone knows for sure what is under the slab. Copper pipe leaks under the slab goes deeper on this.

What the findings mean for the options

If the technician finds an isolated leak on otherwise sound pipe, a spot repair may be a reasonable option. The damaged section is replaced and the line is tested.

If the pipe looks worn along its length, or if there have been repeated leaks, rerouting the line through walls or the attic may be suggested. See slab leak reroute.

In some cases, particularly with several leaks, a partial or whole-home repipe may be discussed. See repiping after slab leaks. The technician explains what led to the suggestion.

Each option is presented with its pricing before work starts. You decide.

What you can and cannot do about the water

This site does not advise on water treatment. It does not recommend, rank or install softeners or filters, and a technician on a leak visit is not there to sell any. If you have a question about your water, the right person is a water treatment specialist, and the answer is not part of a slab leak visit.

What you can do is pay attention. Keep an eye on the meter, particularly after a first leak. Note the date and location of any leak. Tell the technician about previous work. These records help.

The best protection is early discovery. A slow leak that is found early causes less disruption than one that has been running for months. A meter check once in a while costs nothing.

Hard water and copper beyond the Valley

Northern Nevada homes see different water and different foundations. Many older houses sit on crawlspaces or basements, so copper there is exposed and a leak is easier to see and fix. Newer slab subdivisions around Reno, Sparks and Carson City share more with the south.

In rural Nevada, many homes run on wells. Well water has its own characteristics, and mineral deposits can be significant. The technician will ask about the supply when you call.

Nowhere in Nevada is hard water a fault. It is a feature of the region, and homes here are built around it. The point of this page is to explain a pattern, not to alarm.

Keeping a record that helps the next technician

For a home in a hard-water area with copper under the slab, a record is the most useful thing an owner can keep. Note each leak with date, place and line, and any remark about the pipe.

Add the meter photos taken at each check. A series of still readings over time is a good sign, and a drift is a prompt to call.

If a technician opens the floor, ask for a photo of the exposed pipe, and keep it. It is a rare look at what is under the slab.

Where this comes up in Nevada

Mineral-heavy water is a feature of much of the state, in towns large and small. Local pages that cover the homes and conditions around this topic include West Wendover, Hawthorne, Pahrump and Henderson.

Water quality is covered on each of those pages, and the areas page lists the rest.

Common questions

Related reading: slab leak repair and slab leak detection.