Water supply pipe has changed over the decades. Galvanized steel, threaded together at fittings, was common in older construction. Copper, joined with soldered fittings, became widespread in mid-century homes, including many of the slab-on-grade tracts that make up much of Fullerton. Newer repipes often use PEX or copper.
You can often tell what you have by looking at the exposed pipe at the water heater, under sinks or where the main line enters the house. What you see there is a strong hint, though not proof, of what runs under the slab.
How each material usually ages
Copper
- Tends to fail as pinhole leaks or rub-through spots
- Hot lines can wear where they move against concrete or gravel
- The inside usually stays relatively open
- Spot repairs and reroutes are both common
- Some lines may be candidates for lining
Galvanized steel
- Corrodes from the inside, narrowing the pipe over time
- Low pressure and discolored water are common symptoms
- Threaded joints are frequent weak points
- Corrosion is often widespread, not localized
- Repipe discussions come up more often
Identifying your pipe
| What you see | Likely material | Notes |
|---|---|---|
| Orange-brown or dull brown metal, sometimes with green spots | Copper | A magnet will not stick. Joints look soldered, not threaded. |
| Gray metal with threaded fittings; a magnet sticks | Galvanized steel | May show rust at joints. |
| Flexible plastic in red, blue or white | PEX | Usually a sign of a past repipe or reroute. |
| A mix of materials | Partial repairs over time | Common in older homes; ask what runs under the slab. |
What the material can mean for a slab leak
- IfCopper, first leak, pipe at the break looks soundThenA spot repair or reroute of that line is often discussed.
- IfCopper, repeat leaks on the hot sideThenRerouting the hot line or repiping becomes a reasonable question.
- IfGalvanized with low pressure throughoutThenAsk whether repiping makes more sense than repairing one spot.
- IfMixed materialsThenAsk where the transitions are and whether any connections are a concern.
Hard water and pipe material
Fullerton's water, a blend of local groundwater and imported water from the city's water utility, tends to be hard. In galvanized pipe, mineral buildup can add to the narrowing caused by corrosion. In copper, water chemistry is one of several factors in long-term wear. Neither material is doomed by local water, but both are decades old in many houses.
Common questions
Can I tell what is under the slab without opening it?
Not with certainty. Exposed pipe at the water heater and sinks is a good hint, and a plumber may learn more during leak location.
Is galvanized pipe dangerous?
It is mainly a performance and leak concern as it corrodes. If you have questions about water quality, contact the City of Fullerton's water utility.
Should I replace galvanized lines before they leak?
Many owners plan a repipe when galvanized lines show low pressure or rust. A licensed plumber can assess your system.
General information for Fullerton, not a quote or professional advice. In an emergency, call 911.