Workers use many different types of equipment to clean and maintain bridges. Photo courtesy of Washington State Department of Transportation.
Have you ever thought about all the cool jobs associated with bridges? There are underwater welders. Underwater bridge inspectors. Hydro-demolition operators. That last one is actually above water and can be an important part of bridge maintenance.
While Ecology staff don’t get to drive hydro-demolition vehicles, we are involved in the process. Through a water quality general permit, we help ensure the wastewater that comes from regular maintenance, cleaning, washing, and painting of bridges and ferry terminals is properly managed to protect water quality. Given that most bridges, and all ferry terminals, are close to water, this is an important permit.
We are in the process of updating the Bridge and Ferry Terminal Washing general permit, which includes a proposal to add discharges resulting from hydro-demolition activities as part of the permit. We are taking comments on the proposed changes from Dec. 3, 2025 to Jan. 23, 2026.
Keeping bridges clean keeps them safe
Proper maintenance helps keep bridges safe. The activities that help clean and maintain bridges, such as washing, removing and replacing concrete, and stripping old paint, can lead to pollution without proper precautions. Ecology’s permit has the requirements for how to do this important work while protecting water quality.
The Washington State Department of Transportation is the main permittee for these activities, with more than 500 bridge and ferry terminal sites currently covered. The permit can also apply to local government and municipalities, as well as contractors who are working on their behalf. The permit includes best management practices that permittees must follow and requires that wastewater is treated before discharge. This can include using filters for wash water, which removes debris and sediment.
Updating the permit for new technology
We are proposing a number of updates for the permit, including a name change to the Bridge and Ferry Terminal Maintenance General Permit, as the permit covers more than just washing. More substantive updates include:
- Prohibiting bridge washing wastewater discharge to marine waters that are already polluted with copper, lead, or zinc. These metals are harmful to aquatic life and are commonly found in bridge maintenance wastewater. This prohibition is already in place for fresh waterbodies.
- Protecting drinking water wells by prohibiting discharges to ground that would cause or contribute to exceeding the groundwater quality standards in Wellhead Protection Areas.
- Updating the State Environmental Policy Act (SEPA) Checklist and requiring permittees to submit their SEPA documents or attest to any SEPA exemptions.
- Authorizing discharges resulting from hydro-demolition activity to the permit.
Why add hydro-demolition?
This road is ready for repaving after hydro-demolition. Photo courtesy of Washington State Department of Transportation.
Hydro-demolition is a fairly new technology that is used to quickly remove old and damaged concrete from surfaces, including roads. Using high pressure water jets, the machines break up the top layer of concrete while leaving the bridge reinforcing structures, like rebar, intact. The machine then vacuums up the concrete pieces and wastewater. This process leaves a clean bridge platform that is ready for resurfacing. The technology is faster, reduces air pollution and is considered safer for operators.
Some permittees are able to reuse or discharge the wastewater from hydro-demolition to a treatment facility. This is not always possible, so the proposal includes the option to discharge to ground, along with best management practices and monitoring requirements.
We want to hear from you
We are accepting public comment on the draft permit from 9 a.m. on Dec. 3, 2025 through 11:59 p.m. on Jan. 23, 2026. The draft permit, fact sheet explaining the legal and technical basis for the permit, and related documents are on the permit webpage. There are multiple opportunities to learn more about the draft permit, each with question-and-answer sessions, and time to provide testimony. The details for the meetings are below.
Online public meeting and hearing
Jan. 6, 2026, 2 p.m.
Register on Zoom
Online public meeting and hearing
Jan. 7, 2026, 5:30 p.m.
Register on Zoom