A lot of Westside housing is old enough to still have its original plumbing: prewar bungalows in Venice and Santa Monica, older houses throughout Inglewood, and the postwar tracts of Westchester. Homes from those eras were often plumbed with galvanized steel supply pipe.
Galvanized pipe was built to last, but it corrodes from the inside over decades. When it does, the symptoms look like a water quality problem, and people buy filters to fix what is really a pipe problem. Here is how to tell them apart.
Why does discolored water show up in older Westside homes?
Because galvanized steel pipe rusts from the inside. Water that sits in the pipe overnight picks up rust and loosened scale, and it comes out tinted until fresh water flushes through.
The zinc coating on galvanized pipe protects the steel for a long time, and then it does not. Once the steel underneath starts to corrode, rust builds up on the inside wall and flakes off, narrowing the pipe and coloring the water.
Hard water makes it worse. In very hard water areas like Inglewood and Culver City, mineral scale builds up on that rough inner surface too.
How can you tell whether it is the pipes or the city water?
Look at when and where it happens. Discoloration in the first water of the morning, at some taps but not others, or only on the hot side points to your house; discoloration everywhere on the street at once points to the utility.
| What you see | Likely source | What to check |
|---|---|---|
| Brown water first thing in the morning that clears after a minute | Galvanized pipe in the house | Pipe material at the main and under sinks |
| Rusty water only from hot taps | Water heater | The tank's age and anode rod |
| Discoloration at one fixture only | That fixture's supply line or valve | The angle stop and supply line |
| Whole street affected at the same time | Utility work, flushing or a main break | Call your utility |
| Pressure that keeps getting worse | Scale and rust narrowing the pipe | Pressure test and pipe inspection |
Use this table as a first check before you call anyone.
What does a sediment pre-filter do?
It catches particles: sand, rust flakes and loose scale. It does not stop the pipe from corroding, and it does not remove dissolved iron, hardness or the disinfectant taste.
A sediment filter on the main line is useful in two ways. It keeps grit out of fixtures and appliances, and it protects anything downstream of it, like a water softener or a carbon system, from clogging.
There is a catch in an older home. A sediment filter on the main line only sees water coming in from the street. If the rust comes from the pipe inside your walls, the filter is upstream of the problem and never sees it.
When is repiping the answer instead of filtration?
When the pipe itself is the source. Rust that returns every morning, pressure that keeps dropping, pinhole leaks, or visible corrosion at the main all mean filtration is treating a symptom.
No filter repairs a corroding pipe. If the discoloration is coming from galvanized pipe inside the house, the honest fix is to replace that pipe, and a new filtration system can wait until the plumbing it sits on is sound.
When we test water in an older home, we also look at the supply pipe at the main and under the sinks. If the pipe is the problem, we tell you that before you spend money on equipment.
A useful check you can do yourself: run a cold tap first thing in the morning into a white cup, then again after a minute of running. If the first cup is tinted and the second is clear, the color came from water sitting in your pipes overnight. If both are tinted, or every tap on the street is affected, call the utility first.
Can the utility be the cause?
Sometimes, briefly. Hydrant flushing, main repairs and changes in water source can stir up sediment in the street mains for a short time.
Golden State Water's report, for example, describes its hydrant flushing program. If the whole street sees discolored water at the same time, call your utility. It usually clears on its own once fresh water moves through.
Which Westside homes see this most?
Older houses that have never been repiped, in any Westside neighborhood. The age of the plumbing matters more than the zip code.
We cover this on our pages for Inglewood, Venice, Westchester and Santa Monica, where older housing is common.
Brown water in an older Westside home? Pipe Dream Plumbing Co. checks the pipe and the water and tells you plainly which one is the problem. Call (310) 957-1763.