I just bought my first house and have a problem with the cold water. I think it's causing my energy bills to be way too high. All the cold water taps (kitchen, 2 bathroom sinks, shower, toilets, laundry) spew warm water, sometimes hot, when first turned on. Most of the times the water will get cool, never cold, after running for awhile but not always. The water heater is gas. I don't know many technical terms but I'm a pretty good handyman and can often figure out how things work if I have some help. I'm hoping this is a DIY problem because the initial purchase has left me house poor.

Do you have a hot water RECIRCULATING SYSTEM installed?

Thanks,
John

Turn off one of the valves going to the washing machine and then try the cold water in the sink and see if it makes a difference.

If it does change things it means you need a new water valve on the washing machine.

Letmetellu is right, there is a leakage somewhere, your taps are a prime suspect. In particular the type that has one handle and you turn it left for hot and right for cold. Is it at all taps or just one? I assume hot water heater is in basement?

Yeah... some how, one of your valve systems (Faucet, Laundry, etc.) is letting the hot water feed into the cold. This would cause a mixture of both or even only hot to flow through, this would depend on demand in some places and quantity.

I would try it by process of elimination. Under each sink turn off hot and cold valves, any thing that has hot and cold, turn the valves off that are not in the fixture itself. Then go through the house one by one, and turn both on, let the cold run for awhile and see if the problem exists there. If it doesn't then there isn't anything wrong with that one. Turn those valves back off and go on to the next. If you find one that shows the problem, then it probably needs to be replaced, while if the problem exists in all of them, then it could be a major plumbing problem that somebody screwed up.

Junkie nailed ir!
You have a cartridge that has a cross connection that allows cold and hot to commingle. Follow his directions and eliminate the faucets one by one. Good luck, Tom