Most people think that you have a water heater installed and then you just forget about it. Although you could almost get away with that in the past, you will get yourself in trouble if you try that now. The temperature and pressure relief valve has always been a concern. The manufacturers of relief valves recommend that they be tested at least once a year and that they be replaced every 3 years. The danger of a relief valve not working can have disastrous results as captured in this video produced by the Myth Busters


Other concerns are mostly around the maintenance as they relate to efficiency and carbon monoxide safety.

When you drain and flush a tank type heater you are removing debris that collects at the bottom and creates a barrier between the heating source, the fire, and the water. The debris kills the efficiency.

As it relates to carbon monoxide safety there are many things to consider. If the chimney is not adequate you could have a back draft situation. When the chimney back drafts, the exhaust enters the building instead of leaving and that can cause sickness or death. The venting could also be undersized or over sized, also causing drafting problems. Another concern is the quantity/quality of air around the area of the water heater that can greatly affect the creation of carbon monoxide. Too often people want to cram the water heater into a very small space and kind of lock it away. With residential water heaters consuming anywhere from 40,000-200,000 BTU's of gas, you need an adequate quantity of oxygen or make up air to mix with the gas for proper combustion. When the very little oxygen that is available in the room gets used up, the combustion becomes very poor and this creates incredible amounts of carbon monoxide as well as the destruction of the equipment.

The bottom line is to make sure that you are hiring a qualified, licensed, bonded and insured contractor, PLUMBING contractor. In the state of Illinois it is state law that any plumbing, including the installation of a water heater, be performed by a licensed plumber.