All that water damage to their homes and damages could nave been avoided, if home and business owners knew what to do to keep their pipes from freezing. When they lost electricity and heat and that the temperature was going for fall below freezing, all they had to do was to cut off the main water supply to their house or building and open all of the hose bibs and faucets. Any water in the pipes might freeze but will not burst, since the ice would expand in the air spaces. I find it extraordinary that the experts in Texas did not inform the public to do this. They just told them to drip their faucets, which cost lost of water systems pressure.
Some people need to be told not to run their generators inside the house as well. While I have no great love for Texasass, I will refrain from joining in the merriment and glee that MSM seems to be taking at their misfortunes. Well.....except maybe for Houston's baseball team.
maybe it depends on how the water systems are set up. around here, the shut off is after the pipe comes in, so there's a bit of vulnerability before it. the other shutoff is in the sidewall/front yard/street. only the city/town has access
I suppose while we are in the business of making PSAs there ought to be some mention of turning off the water heaters before depressurizing the lines in the house for those who have electric heaters and didn't think to have check valves installed.
OK suppose you have a water heater, a big one. And it has a check valve at the top, a drain valve at the bottom and line in and out at the top. IOW, a normal water heater. Now suppose it freezes. And any water gradually freezes too. What valves should be opened and where will any expansion emerge? Should the drain valve and check valve be opened and the tank drained in anticipation?
Turning off the electric water heater is to protect the upper element from getting turned on if or while it is high and dry, leading to prompt burnout. The tank itself should not be freezing in this sort of brief cold snap, unless it is a seriously old one with no insulation. The piping outside the tank is what is at risk of freezing in the short term.
I would be inclined to drain off at least a quarter of the tank. That would leave plenty of head space even if all the water froze (expanding 9%). I'm not certain Georgina's simplified recommendation will work in all cases. It will depend on where the water freezes first. If the first water to freeze is near the opened hose bibbs or faucets (as might be likely), it can still seal the remaining water in place, which can then burst pipes as it freezes later. Draining the system is better insurance. My hose connections are the frostproof sillcock sort, where the actual shutoff is 12 inches back inside the house where it should never freeze. Nevertheless, in my first few years here I ended up having to replace the one on the west side every spring like clockwork. I would open it up on some nice spring day for the first time of the season and hear water spraying in the basement. It turns out those sillcocks are only reliably freezeproof if all of the water drains out of them, from the 12 inch portion outside of the valve seat. In the old days when they were completely open at the hose end, that wasn't usually an issue. The newer requirement of a backflow preventer on the outlet sometimes gets in the way of all the water escaping. Then over the winter, the water right out at the hose connection end would freeze, trapping the water back toward the valve seat in the house. The trapped water would not itself freeze, but just transmit the hydraulic pressure as the ice plug at the outer end expanded. It would put a tidy little split in the sillcock right back by the valve seat, every time. Of course the water heater, whether electric or gas, must be shut off if the system is to be drained! It's wise to shut it off even if just the main water supply will be shut off. Some homes have an expansion tank near the water heater. Others might not have one; if there is a city water supply that comes in at the right pressure, it is possible that pipe is simply open, and pressure from hot water expansion is simply relieved back out toward the street. If the supply valve is closed (and there aren't other faucets open somewhere) and the heater comes on, the trapped expanding water can rise in pressure enough to trip the heater's pressure safety. In a gas heater that's normally a non-replaceable part of the gas valve, so the whole valve will need replacement. I'm not sure how electric heaters implement it.
On mine, built with a check valve somewhere in the supply line from the street but without an expansion tank, the pressure relief valve on the electric tank would occasionally burp when reheating after a very large draw of hot water. I never witnessed it, but found the evidence in the flowerbed where the relief pipe drained. Then put a bucket under that outflow, and caught some of it. Then obtained a separate adjustable pressure relief valve that could be cobbled onto an outside silcock on the regular cold water line, and played with its adjustment. This would then burp instead of the water tank pressure relief. Adding an expansion tank cured the water expansion burps.
A friend of mine definitely had a gas water heater shut down on pressure safety, from being left on when the incoming water supply was shut off, without burping out the PRV. I don't know if electrics have a similar safety. The traditional water heater gas valves contain a glass bulb that pokes into the tank and will be imploded by excess pressure (at least, that was how I gathered it worked by looking at it), permanently disabling the valve, which then has to be replaced. In this particular heater, anyway, the PRV seemed to be set for a higher pressure than that, making it really the last resort if all other safeties fail.
Was the PRV actually set higher, or might it have failed and the glass bulb was the backup? Typical electrics seem to have a re-closing PRV (how mine burped), and a backup non-self-resetting thermostat that stays off after tripping. Though consumers can press a reset button, and I once had an officemate who fell into that situation without knowing what was really happening. Individually, it seems that all these protective devices have not-insignificant failure rates. So when lazy consumers fail to take heed, and begin repeatedly resetting that backup thermostat daily, real life events can inspire TV episodes ... Farmers Insurance "Hall of Claims: UFH2O" Farmers Insurance 'Sesame Street: Not-So-Handy Monster" MythBusters-Exploding Water Heater #1 (high speed video starts at 2:36) MythBusters - Exploding Water Heater #2
We’ve got a main shut off just inside the crawl space, then another out on the front lawn. The latter requires a special long handled tool to reach down, and I think it can get silt inundated, requires a ladle style scooping shovel to clear out. Would it be the crawl space shut off in our case?? Good topic btw. It’d be good to have a plan, in advance. And yeah, likely varies with your home’s set up. Doubt we’d ever need this info in our location, but who knows.
