Answer: Replacing a how water heater is relatively easy if you have some basic plumbing tools This is particularly true if you have properly set up connections for gas and both cold and hot water pipes. Probably something you can do in less than a half day, even if you have to make a trip to the hardware store for extra parts. Typically the toughest part of the job is the muscle needed to haul the old heater out and drag and position the new one in. If you can also install a pan with attached hose to floor drain, then the next time it happens, you'll reduce your damage. Also don't be cheap, buy the longest warranty possible. Heaters usually fail in the 1st year or just around their warranty period end. But if you don't want to do it yourself, expect to pay through the nose for the short notice + weekend. But in that case, I believe that both Home Depot and Menards have names of people who do this kind of work