Wondering how old your water heater is, and when you think it might be ready to go? It's best, of course, to write things down when you first get a new major appliance (such as when the furnace, air conditioner or dishwasher was installed). But if you didn't record this information, you can still come up with answers, by doing a little detective work. Many products have dates as part of their serial number. If it's not obvious to you, try calling the manufacturer or look for inspection stickers or installer notes. Knowing how old things are helps you plan the future and can eliminate nasty surprises such as unwanted cost and messy floods. And that's the On The House tip for today.