Copper Pipes and Fittings: A Guide for Eagle, ID Homeowners

Type K, L and M: what the letters mean

The letter tells you wall thickness, not pipe size. A half-inch Type K pipe and a half-inch Type M pipe have the same outside diameter, so they take the same fittings. The K wall is thicker and the pipe is heavier. More metal between the water and the outside matters when a pipe is buried or under stress.

Here is how the three types compare in everyday trade use. These are general conventions, so the pipe maker's data sheet and the code have the final word.

Thinner does not mean bad. The job decides the type. A short interior run does not need the wall a buried line needs, and a buried line should never be the thin pipe.

Reading the copper you already have

Walk to the water heater or the main shutoff and look at the pipe. Copper from a pipe maker usually carries a printed stripe along its length, and the color is a trade code. Green is Type K, blue is Type L and red is Type M. Print wears off with age and hides under tape or insulation, so do not count on it.

Size confuses people. Copper is sold by nominal size, so a half-inch pipe measures about five-eighths of an inch across the outside. Measure the outside with calipers or a tape, then ask the supply counter to match it. A wrong guess gives you a fitting that will not seat.

• Bright salmon color is clean copper, and dull brown is just oxidation.
• Green or blue crust at a joint points to a slow weep, so wipe it dry and watch it.
• Beads of water along a cold pipe are usually condensation, not a leak.
• A stain on the drywall below a pipe run means the wall needs opening to see the cause.

Couplings, elbows, tees, unions and adapters

Fittings are the parts that join pipe and change its path. Knowing the names lets you read a parts list or follow a plumber's explanation.

Sweat, press or push-to-connect: choosing a joint

There are three ways to join copper in a home. Each has a place, and each fails in its own way when done carelessly. This table sets them side by side.

Sweating needs a dry, clean pipe. Any water left in the line turns to steam and blows holes in the solder, which is why plumbers drain the line and scrub the copper bright before heating.

Push fittings look easy, and the ease is the trap. The pipe end must be cut square, deburred and pushed to the marked depth. Makers differ on where push fittings may be used, such as inside a closed wall, so read the label and the instructions before you trust one.

Copper or PEX: how the choice gets made

PEX is flexible plastic tubing. It needs fewer fittings because it bends around corners, and it can expand a little when water inside it freezes, though it is not freeze-proof. It must stay out of sunlight, and it is not meant to touch hot flue parts.

Copper is rigid, tolerates heat near a water heater and does not sag between supports. It costs more labor to join well, and it can develop pinholes as it ages. Neither material is right for every house, and the code and the maker decide where each may go.

A custom home built between 2006 and 2019, like those in The Shores or Two Rivers, could have either material. Look at the pipe before you assume. If copper is failing in several places, patching becomes a habit, and whole-house repiping is the question to bring to a plumber.

Pinhole leaks and what to ask about them

A pinhole leak is a tiny hole in a copper wall. It shows up as a green stain, a damp spot on drywall or a fine mist behind a wall. The causes are mixed, and finding the one at work means looking at the pipe, not guessing.

Water chemistry can play a part. We do not know what is in your water. Your supplier might be Veolia Water Idaho, the City of Eagle or a private well, depending on the address. Ask your water utility for its annual water quality report, or have your tap tested.

One pinhole can often be cut out and closed with a coupling. Several pinholes in different rooms point to wear through the whole system. If water is spraying or a stain is growing, shut the main valve and call for burst pipe repair, which our 24/7 dispatch line handles.

To check for a leak you cannot see, try the EPA meter test. Note the meter reading, use no water for two hours, and read it again. If it moved, you probably have a leak somewhere.

A checklist before you cut into a copper line

1. Shut the water off at the main valve inside the house and confirm it holds.
2. Open a faucet at the highest point and another at the lowest to drain the line.
3. Identify the pipe size and type, and buy fittings that match.
4. Cut square with a tubing cutter, then deburr and clean the ends bright.
5. Match the joint type to your tools and your skill, not to the fastest option.
6. Turn the water on slowly and watch each joint for a bead of water.

Stop and call a licensed plumber if the main valve will not close fully, if the pipe is crusted for a foot or more beyond the leak, or if the run sits behind a finished wall. Those are signs the problem is bigger than the visible spot.