Plumbing After a Wildfire: Water, Gas, and Rebuilding

Is the water safe to drink after a wildfire?

Not until someone tests it, if the fire got onto your lot or the lots around it. Santa Rosa learned this the hard way. After the Tubbs Fire in October 2017, benzene and other contaminants turned up in the water serving the 13 homes still standing in the affected part of Fountaingrove. The city put those homes under a do not drink, do not boil advisory on November 10, 2017, and it stayed in place until October 11, 2018. The city tells the whole story on its water quality advisory page.

Boiling is for germs. Benzene is a chemical, which is why that advisory told people not to boil the water either. Until you have test results, drink and cook with bottled water, and ask your water provider whether your street is under an advisory. If you are on a private well, the well and the piping inside the house both need testing.

How does a fire get into the water pipes?

The pipe does not have to burn. Researchers at the Purdue Center for Plumbing Safety heated the plastic pipe most houses are plumbed with, PEX, HDPE, polypropylene, PVC, and CPVC, and found that benzene was generated by and leached from all of them at 150°C, which is 302°F, and hotter. Once the pipe cools, the chemicals keep coming out into the water sitting in it.

In Santa Rosa, the city's investigation found the worst of it in the water services, the lines that run from the main in the street to each meter, and the city replaced them. The pipe on your side of the meter belongs to you. If any plastic in your supply system was exposed to heat, get the water tested before you trust it, and plan on replacing that pipe if the results come back bad.

When will PG&E turn my gas back on?

Do not turn the gas on yourself, even if you can reach the valve. PG&E's wildfire recovery guidance says PG&E or another qualified professional has to do a safety inspection before service is restored, and a crew then comes back to turn the meter on, run safety checks, and light the pilots. If you are back home and still have no gas, PG&E's line for that is 1-877-660-6789.

Before any pilot gets lit, have someone look at the water heater. A tank that sat through heat and smoke needs its gas control, vent, and relief valve checked. If it has to be replaced, a like-for-like 40 gallon gas tank runs $1,800 to $3,200 installed with the code items. Our water heater team can do the check and the swap on the same visit.

What should get checked in a house that survived?

• The water line from the meter to the house. Find out what it is made of. If it is plastic and the fire reached the yard, test the water first and price a replacement.
• Hose bibs, irrigation valves, and backflow devices on the outside of the house. Look them over for heat damage before the irrigation goes back on.
• The water heater, before anyone lights it.
• Any gas pipe on an outside wall. Leave that one to PG&E's inspection.

If the service line needs to go, our water main and service line crew replaces it from the meter to the house and handles the permit.

What does the plumbing need when you rebuild?

A rebuilt house is new construction, so it goes in under today's code, and in California that means a residential fire sprinkler system. Sprinklers change the size of your water service, because the line has to deliver enough flow to run them.

According to Santa Rosa's rebuild guidance, most meters in the city's burn areas were 5/8 inch on 3/4 inch service lines. The meter can go up to 3/4 inch for a small cost, and in most cases that upgrade plus larger pipe from the backflow preventer to the house gives a sprinkler system the water it needs. Residential backflow devices come in 1 inch or 1 1/2 inch, and the pipe between the meter and the backflow device has to match the device.

Pick the sprinkler contractor early. The city notes that a C-16 fire protection contractor cannot design a system they do not install, so whoever designs yours will be installing it too, and the water service has to fit their design before the plumbing plans are final.

Two more jobs belong at the start of a rebuild, not the end. Camera the old sewer lateral while the lot is still open. Debris removal drives heavy equipment over it, and an inspection runs $150 to $500, a lot less than finding a crushed line after the new driveway is poured. Then size the new gas piping for the appliances you actually plan to run. PG&E will not set a meter until the gas work has its permit and has passed inspection, and we pressure test the piping for that inspection. Our gas line page covers what we install, and the Sonoma County permit guide covers who issues what.