"Dragnet" made its TV debut on this day in 1951. In one episode detectives Friday and Smith investigated a 10-12 -- potential scalding. Not a pretty picture. "Open up, hot-water police got a report you have an old water heater and overly hot water. Way too hot." Just one second of exposure to 150-degree water can cause a serious third-degree burn. It's not common knowledge, but sediment buildup and drifting thermostat settings can cause water heaters to grow hotter with age. So, test your water with a thermometer, and keep it between 130 F and 140 F. This can still cause a burn if you slip and grab the faucet handle as you fall. Your best answer -- an anti-scald shower valve that keeps water temperature safe, no matter what. With many plumbing codes for new construction, it's the law and all manufacturers now offer affordable scald- control models. And that's the On The House Tip for today.