Septic systems require regular maintenance.

• Position: Eye on Ecology

More than 26,000,000 homes in the U.S.--one in five households--depend on septic systems to treat wastewater, according to the Environmental Protection Agency, Washington, D.C. If not maintained properly, septic systems can contaminate groundwater and harm the environment by releasing bacteria, viruses, and household hazardous waste into local waterways.

"By taking small steps, homeowners not only protect our nation's public health and keep our water clean, but save money and protect their property values," says Joel Beauvais, deputy assistant administrator for the Office of Water.

EPA tips for homeowners include:

Protect it and inspect it. Have your system inspected every three years by a qualified professional or according to state or local health department recommendations. Tanks should be pumped when necessary, typically every three to five years.

Think at the sink. Avoid pouring fats, grease, and solids down the drain. These substances can clog a system's pipes and drainfield.

Do not...