Using rain barrels or other containers to collect rainwater was illegal in Washington State until October 12, 2009. That was when the state's Department of Ecology reversed a long-standing policy that made it illegal to harvest rain pouring from roofs. For many years, it was legal to purchase but not to use rain barrels in Washington. The problem flowed from old-time water laws in semi-arid western states.
Western Washington, including Seattle, is renowned for its rainy weather from fall through spring, averaging 30 to 60 inches annually in the lowlands and double that figure in the Cascade foothills and the Olympic Peninsula. But the region east of the Cascade Mountains, which includes Spokane, gets one-third that amount and is semi-arid, similar to western states such as Colorado and Utah. The Washington Department of Ecology says it might seem hard to imagine a need for rain barrels in Seattle, but there is little rainfall along the coast during the time of greatest need -- summer.
Western Water Law
Western water laws are complicated and date back to pioneer days in the mid-19th century. Many are based on what Colorado State University refers to as a "first in time, first in right" philosophy that allowed farmers and other settlers to obtain court orders allowing them to appropriate certain amounts of stream flow annually and forever. In time, western water became over-appropriated, and there wasn't enough to accommodate all who held rights to it.
Although Washington didn't actively enforce its old, no-rain-barrel rule for homeowners, the policy created problems for developers of eco-friendly buildings who wanted to collect rainwater for purposes such as flushing toilets, according to Sightline Institute, a northwestern organization focused on environmental sustainability. Because of Washington's backlog of applicants for water rights, the Institute says, the old policy made it easy for anyone opposed to construction of a green projects to slow it down by contesting water rights.
Reasons for Reversal
The new policy allows property owners to use rain barrels and underground storage systems to collect rooftop runoff for use on the property where it is harvested. However, the state can step in if the practice negatively affects existing water rights or harms the water supply. The Washington Department of Ecology notes that rainwater collection aids storm water management and is an ecologically friendly way to provide for home irrigation needs. One major aspect of this ecological friendliness that proponents of rainwater harvesting cite is that it minimizes the amount of municipally treated water needed for watering yards.
Laws in Other States
Colorado revised its stringent law against rainwater harvesting in July 2009. Now landowners who have wells and don't have access to municipal water supplies may harvest rain. Utah rescinded its law against the practice in May 2010. The new Utah law allows anyone to collect rainwater for use on the property where it is collected. But the size and number of collection containers are limited.