Water systems · Water supply lines
How long do water supply lines last?
The pipes behind the walls outlast nearly everything else in the house, and the longest warranty in the trade is still shorter than the shortest of them: Uponor's 25-year PEX term against baseline figures of 40 to 75 years. That term also depends on whose fittings went on the pipe and who was holding the tool.
Updated
The gap: warranty ends at 25 years; typical service life ends around 75 years. The material typically outruns the paper by about 50 years. Warranty document (Uponor, checked 2026-08-27)
Typical service life: 40–75 years
The baseline chart's supply-line rows span this range: PEX at 40 years, copper water lines at 70, plastic water lines at 75, and — in a second set of rows on the same chart — copper and plastic water lines at 50 apiece. The chart disagrees with itself by 20 years on copper, which is a fair picture of how much the water, rather than the pipe, decides the answer.
Tier 3 · baseline chart (undated) Range from InterNACHI — Standard Estimated Life Expectancy Chart for Homes, checked 2026-08-27.
Freezing is the one failure mode that ignores the material entirely: PEX, copper, CPVC and galvanized pipe in an unheated crawl space, an attic run or an exterior wall are all at risk at the same temperature, and no manufacturer's term covers it. Warm regions trade freeze risk for chemistry — chlorinated, aggressive or high-velocity water works on pipe every day of the year instead of a few nights of it.
By material
| Material | Typical service life | Source |
|---|---|---|
| PEX | ~40 yrs | Tier 3 · baseline chart (undated) InterNACHI |
| Copper | 50–70 yrs | Tier 3 · baseline chart (undated) InterNACHI |
| Galvanized steel | 40–60 yrs | Tier 2 · trade / standards literature CorrView International |
| CPVC and other plastic supply lines | 50–75 yrs | Tier 3 · baseline chart (undated) InterNACHI |
What the warranty paper actually says
Uponor (Limited warranty on ProPEX pipe, fittings and rings) publishes a 25-year limited, conditional warranty. The 25 years applies only when Uponor pipe, Uponor fittings and Uponor rings are installed together as one system. Put a non-Uponor fitting or ring on that same pipe and the pipe's term falls to 10 years; run an Uponor fitting on someone else's pipe and the fitting's term falls to one year. The whole thing is conditional on installation by a licensed plumbing contractor Uponor recognizes as having completed its training, and on the pipe never seeing pressure, temperature, velocity or water chemistry outside the published specification — chemicals in the water and exposure to ultraviolet light are both named exclusions. Damage to the house itself is reimbursable only for a failure inside the first ten years, and any claim has to be filed within 30 days of the suspected failure.
The warranty document itself , checked 2026-08-27.
What shortens it
- Water chemistry: aggressive, acidic water thins copper from the inside, and chlorine and chloramine work on plastic pipe every day it is in service
- Velocity — undersized pipe running fast erodes copper at elbows, tees and the first few inches past a fitting
- The hot side and any recirculation loop, which age every material faster than the cold pipe running beside them
- Sunlight on plastic pipe, whether on the job site or through an uncovered crawl space vent; ultraviolet exposure is a written warranty exclusion
- Water hammer and pressure surges from fast-closing valves and appliance solenoids
- Contact with dissimilar metals or the wrong hangers, which sets up galvanic attack and abrasion at every support
Signs of wear to look for
- Pinhole leaks, or green-blue staining and crusting under copper at joints and elbows
- Rust-colored water on the first draw of the day, with pressure that has slowly fallen off at the top floor — the classic pattern of galvanized pipe closing in on itself
- Plastic pipe or fittings gone chalky, brittle or finely cracked where they are exposed to light
- Weeping at crimp rings, compression nuts and valve stems that dries to a white or green ring
- A water meter dial that keeps moving with every fixture in the house closed
- A warm patch on a slab floor, or the sound of water running with nothing open
A leak inside a wall, under a slab, or in the buried line between the meter and the house is a question about opening up the building to find it — that is an inspection question, not a web-page question.
Related water systems
- Water softener about 20 yrs
- Sump pump about 7 yrs
- Well pump about 15 yrs
- Well pressure tank 10–25 yrs
- Sewer line 50–80 yrs
- Vinyl pool liner about 10 yrs