What gets checked
The inspector operates fixtures in a normal way and looks at everything that is visible and accessible:
- Water supply: pipe material, visible leaks, corrosion, and static water pressure at a hose bib.
- Drain, waste and vent: how sinks, tubs and showers drain, signs of past backups, venting where visible.
- Fixtures: faucets, toilets, showers, tubs and their seals.
- Water heater: type, approximate age, venting, seismic straps, temperature and pressure relief valve and its discharge pipe.
- Fuel supply: visible gas piping and the main shutoff location.
Pipe materials and what they signal
| Material | Era commonly installed | Common concern |
|---|---|---|
| Galvanized steel | Before the 1960s | Internal rust narrows the pipe, low flow, leaks at threads |
| Copper | 1960s onward | Pinhole leaks in some water conditions; generally durable |
| Polybutylene (gray plastic) | About 1978 to 1995 | Known for failure at fittings; many insurers ask about it |
| PEX | Late 1990s onward | Durable; watch for UV exposure and poor support |
| Cast iron drain | Before the 1970s | Cracking and scale buildup inside |
| ABS drain (black plastic) | 1970s onward | Generally fine; some 1980s batches were recalled |
Many Southern California homes have been repiped, sometimes partially. A house with copper under the sinks can still have galvanized pipe inside the walls.
Water heaters and California law
California Health and Safety Code section 19211 requires water heaters to be braced, anchored or strapped so they don’t topple in an earthquake. A falling tank can break the gas line, which is a fire risk. Sellers must certify that the water heater is strapped. Inspectors also check:
- Two straps, one in the upper third and one in the lower third of the tank.
- A flexible gas connector rather than rigid pipe.
- A relief valve discharge pipe that runs to the outside or an approved location, not stopped short.
- Proper venting and clearances, especially in garages, where the burner should be raised 18 inches above the floor unless the unit is rated otherwise.
- A drain pan when the heater sits above living space.
Tankless units are now common. They need periodic descaling, especially in hard-water areas, and a dedicated gas line or electrical circuit sized for them.
Leaks and moisture
Inspectors look under every sink, around toilets and at ceilings below bathrooms. A moisture meter or thermal camera may help, but it only detects moisture at the time of the inspection. A dry stain may be old, or it may only appear when a particular shower is used. Ask the seller about any past leak repairs and get the invoices.
Beyond the standard inspection
Consider adding a sewer camera inspection for homes built before about 1980, homes with large trees near the lateral, or any home with slow drains. Slab leaks, which are common with older copper under slabs, can sometimes be found with a dedicated leak detection service.
Common questions
Does a home inspector check the sewer line?
A standard inspection runs water through fixtures and watches how drains perform, but the buried line to the street isn't visible. A sewer camera inspection is a separate service and is worth it for older homes and homes with large trees.
How old is too old for a water heater?
Tank water heaters often last 8 to 12 years. Inspectors look at the manufacture date on the label, rust at the base, leaks at connections, venting and the pressure relief valve. Age alone isn't a defect, but plan for replacement once a tank is past ten years.
What is a pressure regulator and do I need one?
A pressure reducing valve lowers street pressure before it enters the house. Many Southern California neighborhoods have high municipal pressure, and inspectors often recommend a regulator when they measure more than about 80 psi.