The Associated Press

OLYMPIA — A state Supreme Court decision has upheld stricter stormwater rules for building projects.

The Daily Herald reported the decision is a victory for clean-water advocates looking to protect Puget Sound from toxic runoff.

At issue was whether new low-impact stormwater regulations that took effect statewide in 2015 would apply to projects that were submitted earlier, but had not yet broken ground.

In last Thursday’s ruling, all nine Supreme Court justices agreed that projects predating mid-2015 would not be protected indefinitely under older, less-strict rules. That reversed an earlier appellate court decision.

“It’s a clear validation that protecting public waterways is a paramount concern,” said Chris Wilke, executive director for Puget Soundkeeper, one of the petitioners to prevail in the suit.

“These waterways belong to everyone in the community. If one specific entity is inconvenienced, it’s not a valid reason for letting pollution occur indefinitely.”

Developers view the rules as a violation of their property rights. They object to the time and money it takes to comply.

Environmentalists counter that the issue is crucial because stormwater is the largest source of toxic pollution in Puget Sound.

Motor oil, pesticides and other pollutants pose an ongoing threat to salmon, orcas and other marine life, as well as commercial fishing and swimming, they say. Those substances are carried into streams, rivers and marine waters through runoff from parking lots and other hard surfaces.

The new drainage code differs from the old one by requiring low-impact development whenever feasible. That means more rain gardens, stormwater vaults and permeable pavement for all new development in the county.

The case stems from a 2013 decision by the Pollution Control Hearings Board concluding that stormwater regulations were different from land-use rules.

Under Washington state law, property developers are protected under the land-use rules in place at the time they submit a building application.

It’s a principal known as vesting, which allows developers to build projects under rules out of date by years or even decades.