if a shower is taken for 30 minutes.thay would be the 75 gallons of water.. sounds right but its not..the heater will actually give you only about 50-60 gallons of not water because the tank is filling with cold as you use the hot it is also mixing so..if you take a shower for 30 minutes you will deplete the heater, then it needs to reheat the water. but the next person jumps in the shower. he will get cooler hot water and less of it..it all boils down to the length of showers and how lon inbetween them. when your house was built a misunderstand of a water heater system happenrd instead of a huge heater seperat heaters for different baths would have been the way to go this is also the reason of your high gas bill you have a hugh vessal of water, the gas has got to keep that vessal at the temp you want it..every time you use hot water the heater has got to come on and heat up the water to thee desired temp. a larger vessal will cost more than a smaller vessal to keep warm.. my opinon..water heater to big...need to split the system upinto 2 systems,and..with the price of fuel.the way it is now. i suggest to switch to 2 50 gallon electric heaters AND the heaters get put on timmers. if you both work heater off 9pm-5am on 5am-8am off8am-4pm something like that the ages of your children also have a big factor in all of this. teen agers stay in the bathroom or on the phone i never thought i would be telling people to go with elec water heaters. but my fuel price went up ti $4.a gallon a few mths ago. went down..but i think it will go back up

If you are away from this home for 10 months out of the year, you should be shutting the main water valve off (At meter) and draining the entire system, including the water heater. This eliminates any possible water damage that could occur. Provide mineral oil or product that will not evaporate in each waste trap. While your using this home there are several products which can reduce/eliminate water damage. I talked to an Insurance adjuster once, he said the most claims he gets from homeowners is Washing machine hose breaks. There are expensive products which can sense current flowing to the washing machine and will open the water valves only when the washer is turned on and also have a water sensor as a backup safety (Watts product A2C-WB-M1). The link below has inexpensive burstproof stainless steel braided hoses, which have a special valve that closes if the flow is too fast, as in a hose break. I have them in my home, bought them at Home Depot. Just another consideration, Dan Martyn Here is a link that might be useful: Watts

Hi Sara in philly.....I'm just outside Philly - Chester County. If you search on "water heater forum" you will find some great forums with lots of info including some on how to self-diagnose things with your heater. I'm assuming some here will feel it's best to get a plumber to do this, BUT, from reading what the pros suggest, some things can be self-diagnosed with the proper tool - a measuring device of some sort, I think, that measures the junk in the tank....There's also a step-by-step site on things to check out with problem water heaters, but unfortunately, I didn't save the site. There's a wealth of info to learn on those sites. Good luck.

What is all the hot water needed for? A gas heater doesn't have to be in a well ventilated space because waste gases must be vented to the outdoors. It just needs source air and that's very easily done. Running a gas line is never a structural issue...it's a money issue. If two 50 gal units is a small fortune to operate...wouldn't one be 1/2 a small fortune? Still sound like a lot. I mean it's not like the second unit would cost 2x,4x,10x more than the first unit. That is kind of the deal if you want lots and lots of hot water on demand...it costs money. Solar can get you lots of pretty cheap hot water, at least DIY. The units you buy seem kind of expensive to me for what they are.