The county water supply had a main break this morning. My house sounded like water was running with leaks all over the house. I ran around checking. My in water line from the street into my house was very HOT. My house was sounding like it was going to blow up. I went and turned the gas off the hot water heater. Turned off the main line in my house from outside. Then I went outside and turned off the water at the meter underground. Talked to neighbors, some were having the same thing going on. They sll decided to do as I did and cut the water off and the gas to the hot water heater off. My question what happened and how dangeous is this if I was not home and I assume it was sucking the hot water heater empty and it was still heating the tank. Would the tank blow up or damage my pipes. About 15 years ago a water break happened from the county. When they turned the water back on I had to replace all the cartridges in my sinks etc. and dig up my front yard as it blew up the underground (my line) where is was contacted near the house. They blew so much air into my pipes with debris that it was very costly on my part. What would have happened if I had not cut stuff off? How can I fix this so this will not happen again? What if I am not home if it happens?

This message has been edited. Last edited by: Freecs,

I think a check valve between your meter and the house shut off would stop any flow from the the house to the outside water system, but it wouldn't stop anything the utility company blows through the lines. prehaps a filter in the line before the check valve would help
This is just my idea, maybe Frodo, who is a plumber will have a better idea

nona is correct. what happened? i answered this thread 10 min ago and the answer disapeared. crazy computer
what hapened was the city piping broke. causing a negative flow condition.
it sucked youre piping system out. its called back syphonage
the noise you heard was your heater water boiling because the tank was dry. not good.. but your protected by your t an p safety valve located on your heater.
have a plumber instal a ck valve in the horizontal piping in your yard. install a valve on the street side of valve and a union on the other side. cover with a black irrigation valve box
there are 2 types of ck valves, a swing ck and a spring ck
for full flow use a swing ck installed on the horizontal ONLY
a spring ck is installed on the vertical and causes a small amount of restriction to flow
good luck

This message has been edited. Last edited by: Frodo,

Thank you both sooooo very much. Was cutting off water, turning the gas off unnecessary? Would it have sucked all the water out of the tank if I had not cut the water off? If so would the tank blow up if it is heated while empty? Thanks (:

no..your tank has a temp. pressure relief valve
called a t an p valve located on top of your heater
that brass thing with the little chrome handle
if heater reaches a critical temp or pressure it will blow off
but... heating a dry tank does not do the tank anygood at all.
also your t-stat may be hurt
if it stops heating, ck that
what you experienced is not a common thing
but does happen. i go to classes to learn about it
just think if your hose was laying on the ground.right were you had just ferterlised, the back syphonage would have sucked the ferterliser into your piping system. and you come home, all happy and get a drink of cool water
i drink bottled water

If your water heater was electric and the elements became exposed to air rather than water they would probably burn out. It wouldn't be great for your gas water heater to run with the tank partially filled, it would probably be pretty bad if it were empty.

If you add a check valve you need to install an expansion tank on the cold water line at the water heater. The reason is as water is heated it expands. If you don't have an open tap the expanding water pushes out towards the water main, if you install a check valve it can't push out into the main and the tank becomes over pressurized. This will cause your Temperature / Pressure valve to open sending hot water on your floor. It would be a regular occurrence every time your water heater runs. Our town was going to install check valves on our water lines to prevent backflow into the main which could cause contamination from say a garden hose that had a hose end sprayer on it that was used to spray garden chemicals. The anti-siphon on your toilet filler is to prevent that water from getting pulled back into the system in the event of a water main break.

The tanks run about $40 at my local Lowe's or Home Depot.

http://www.lowes.com/pd_160680...e%2Btanks&facetInfo=

This message has been edited. Last edited by: Sparky617,