Gray Water


Gray Water in the News

Gray Water Reuse in Montana MONTANA WATER Newsletter, June 2011

Gray Water May Help Stretch Precious Resource The Montana Standard, December 2007

What is Gray Water?

Gray water is waste water that does not contain human waste. In other words, gray water is the water that comes from washing machines, dishwashers, showers, and sinks. This water can be recycled on-site and used for irrigating landscape.

How Does it Work?

A separate set of pipes will be installed for a gray water system. Water from toilets and kitchen sinks will go into the sewer or septic system. Water from all other sources will go into a basic filtration system to remove particles. Filtered water is directed to fill toilet bowls or to an underground irrigation system to water lawns or trees. Homemade and professional gray water systems have been approved and installed around Montana since becoming legal in 2007.

Legal Status

Gray water reuse was illegal in Montana until the 2007 Legislative Session, where SAVE helped to bring this conservation solution to the state. Since that time, the Montana Board of Environmental Review has passed rules for gray water systems.

"The gray water legislation from this and last session, is a tribute to the legislative process that has brought forth a great opportunity to conserve water," said Matt Elsaesser, SAVE's Director.

During the 2009 Legislative Session another major step was taken for expanding the use of gray water systems across Montana. Amid concerns that current laws were too restrictive, House Bill 285 lifted the limitation that only single homes may install gray water systems. It was sponsored by Rep. Michelle Reinhart (D-Missoula). Many legislators hoped to use the expanded law to engage a broader coalition of builders, pumpers, architects, and homeowners to ensure good rules for gray water systems follow the law. Now a law, this expands the use of simple technology for water recycling into multi-family homes and commercial buildings.

The 2011 legislature passed an incentive for installing gray water reuse systems in new residential construction. The tax abatement reduces property taxes by 9% each year for 10 years, and applies to both multi and single family residences.

Daily Habits - Gray Water Issue