Department of Ecology – Permits & UIC

Construction Stormwater General Permit

Many construction sites will need to apply for coverage under the CSWGP. Construction site operators are required to be covered if both of these apply:

Your construction project disturbs land* through clearing, grading, excavating, or stockpiling of fill material.
- Sites that disturb one acre or more.
- Sites that are smaller than one acre that are part of a larger common plan of development that will ultimately disturb one acre or more and discharge stormwater to surface waters must apply for a permit.
- Sites of any size discharging stormwater to state waters (Waters of the State) that we determine to be a significant contributor of pollutants.
- Sites of any size that we reasonably expect to cause a violation of any water quality standard.
There is any possibility that during construction, stormwater could run off your site or enter a conveyance system that leads to surface waters. In almost every case it does. If the location of your site poses no possibility that rainfall or snowmelt could leave the site or enter a waterway, you do not need a permit.

*Count the cumulative acreage of the whole project, whether it’s single or multiphase. Include off-site disturbance acreage from support activities related to the construction site. This applies if your project is a portion (less than one acre) of a larger project planned over time.

You can find the Notice of Intent to apply for coverage under the “To apply for coverage” dropdown on the Department of Ecology webpage.

Industrial Stormwater General Permit

This permit requires coverage for new and existing point source discharges of stormwater to surface waters of the State, including groundwater, that are associated with industrial activity identified under the coverage sections contained in S1.A.3 or listed in Table 1. This includes private entities, state and local government facilities, and new facilities and existing facilities. Facilities conducting industrial activities listed in Table 1 or referenced in S1.A.3 shall apply for coverage under this permit or apply for a Conditional No Exposure exemption, if eligible (Condition S1.F). The Department of Ecology (Ecology) may also require permit coverage for any facility on a case-by-case basis in order to protect waters of the State (Condition S1.B).

Facilities engaged in any industrial activities included in Table 1 on page one of the permit shall apply for coverage if stormwater from the facility discharges to surface waters of the state. The North American Industry Classification System (NAICS) groups generally, but not always, associated with these activities are listed in Table 1.

You can find the Notice of Intent to apply for coverage under the “To apply for coverage” dropdown on the Department of Ecology webpage.

Underground Injection Control Wells (UIC)

What are injection wells?

Underground Injection Control (UIC) wells — or injection wells — are structures built to allow fluids to flow into the ground (usually) under the force of gravity. The most common in Washington are known as drywells.

An injection well is designed and built:

Deeper than the largest surface dimension.
To contain an assemblage of perforated pipe.
As an improved sinkhole.
As a chamber or vault designed to capture and infiltrate stormwater.

Examples include: sump pump, drywell, drainfield, an infiltration trench containing perforated pipe, a stormwater chamber, and temporary injection points.

The many uses of injection wells

Injection wells are used to manage stormwater, remediate groundwater contamination, replenish aquifers, and as return-flow wells for heat pumps. See our other uses section below for more details.

We protect groundwater by regulating injection wells

We minimize the potential for groundwater contamination from UIC wells by regulating: