At a glance
- Galvanized steel
- Common in homes built before about the 1960s; corrodes from the inside
- Typical failure
- Leaks at threaded joints, rust-colored water, falling pressure
- Copper
- Long-lived but can develop pinhole leaks in some conditions
- Who evaluates it
- A licensed plumber; repiping usually needs a permit
- Season
- Can fail at any time of year, not just in cold snaps
How old pipe fails
Galvanized steel pipe was coated with zinc to resist rust, but over decades that coating wears through and the inside of the pipe builds up scale. The wall gets thinner, especially at threaded joints where the metal was cut. The result is usually a weeping joint or a crack at a fitting, though a badly corroded section can split when it is bumped during other work or stressed by a pressure change.
Copper is more durable, and many Denver homes have copper that is still sound. Pinhole leaks do happen, though, and they are often tiny at first: a spray inside a wall that soaks insulation and framing for weeks before anyone sees a stain. Some houses have a mix of materials after partial repairs, and the joints between different metals can corrode faster if they were not connected with the right fitting.
Mixed or patched plumbing is common in older neighborhoods like Highland, Baker, Congress Park and Park Hill, where houses have been remodeled several times. A plumber can tell you what you have and how much life it likely has left.
Age failure versus freeze break
The difference matters for repairs and can matter for an insurance conversation.
| Corrosion or age failure | Freeze break |
|---|---|
| Often a slow drip or weep before a larger leak | Usually sudden, often noticed when the ice thaws |
| Rust staining, mineral crust or green corrosion at joints | Lengthwise split or bulge in the pipe |
| Can happen in summer or in a heated interior wall | Located near exterior walls, garages or crawlspaces |
| Neighboring sections may be just as worn | Surrounding pipe may be in reasonable condition |
What to do with what you find
- IfOne pinhole leak in otherwise clean copperA spot repair may be reasonable. Ask the plumber to look at nearby runs and note the water pressure.
- IfRepeated leaks or rusty water from galvanized linesAsk for a repipe estimate and whether a permit is required from Denver Community Planning and Development.
- IfA leak was found behind a finished wallHave moisture mapped before the wall is closed; slow leaks often wet more area than the visible stain suggests.
- IfLow pressure on upper floors onlyThis can be scale buildup in old galvanized pipe. Ask the plumber whether the line should be replaced before it fails.
Warning signs worth a plumber visit
- Brown or orange water when a tap first opens after sitting
- Pressure that has dropped over months or years
- White, green or rust-colored crust on visible joints
- Damp spots on ceilings below bathrooms without an obvious overflow
- A water bill that rises with no change in use
- The sound of running water when every fixture is off
Common questions
Does a repipe always mean opening a lot of walls?
Plumbers often route new lines through closets, basements and attics to limit openings, but some drywall or plaster work is usually needed. Ask for a plan showing where walls will be opened.
General information for Denver, not a quote or professional advice. In an emergency, call 911.