Every five years we review and update each of our general permits. The Sand and Gravel General Permit covers approximately 850 facilities that produce and process sand and gravel, crushed rock, concrete, and asphalt to support the state’s growing need for construction materials for roads, highways, new housing, and commercial properties. There is a large variety of types of facilities regulated by the permit, from gravel pits, rock quarries, and similar mining operations, to concrete batch plants, concrete or asphalt recyclers, and hot mix asphalt operations. The water used at these sites, such as process wastewater, stormwater, and water from mine dewatering contain similar types of possible pollution. Since the water they discharge is similar, we use the Sand and Gravel General Permit to cover all of these types of facilities and ensure that their wastewater and stormwater discharges are controlled and treated to prevent pollution of Washington’s waterways.
We’re sharing about the updates we are proposing for the permit, information on how you can learn more, and how to join the conversation.
Concrete rubble study helps inform updates
Concrete is the durable material we commonly see used for sidewalks or building foundations. It is an impervious surface. This means rainwater doesn’t seep through it. Instead, water runs off of it. However, when concrete is broken up into rubble and stored in piles waiting to be recycled, water can flow through the piles. Water that mingles with concrete can pick up pollution and flow to waterbodies or groundwater. We recently led a water quality study at facilities covered by the Sand and Gravel General Permit that create and recycle concrete to characterize the amount and type of pollution that may be present. Read our 2024 blog for more information about the study.
The study’s preliminary results, and our previous studies, provided key insights for the current permit update. We found that the majority of parameters we sampled met our water quality standards. However, we did find a few that exceeded the water quality standards, meaning they pose a threat to water quality. Water quality standards are the backbone of our regulations and set the pollution limits for how clean lakes, rivers, groundwater, and marine water needs to be for the health of people and aquatic species. With a few site-specific exceptions, we found that although arsenic and manganese were found to be high, they were generally below background levels that naturally occur in Washington. We found high levels of (dissolved) chromium and total dissolved solids (TDS) at some sites.
Although we have completed our analysis, we are in the process of finalizing the report for publishing.
Proposed changes
We are proposing significant changes to the Sand and Gravel General Permit. These changes are intended to better protect water quality for rivers, streams, and groundwater. We recognize that some of the proposed requirements in the draft can lead to new or increased costs for facilities, including increased cost for added monitoring and best management practices.
Proposed changes include new vehicle washing requirements such as clarifying that all soap or solvent impacted water is collected and disposed of properly, clarifying sediment track out requirements, and requiring additional best management practices for some sites.
Our workshops in September (see below) will include a presentation with more details on all of our proposed changes.
Additional proposed monitoring requirements
We are proposing new and additional monitoring for hexavalent chromium and total dissolved solids.
Our study measured dissolved chromium. Based on what we observed at the sites in our study, our concern is that hexavalent chromium could be present in the oxidized, high pH conditions we saw. Hexavalent chromium is more soluble, toxic, and mobile than other forms of chromium and has been shown to negatively impact human health and the environment.
We are proposing to add new sampling for hexavalent chromium at concrete facilities that send wastewater to waterbodies. We are proposing monthly sampling because the amount of hexavalent chromium may be related to the pH (acidity) of the water, which is already required to be sampled monthly.
During the concrete study we also found several facilities with elevated levels of total dissolved solids. Total dissolved solids are the amount of materials that are dissolved in water, such as salts, metals, and minerals. During the study, elevated dissolved solids were not always caused by concrete rubble and can also come from rinse or wash water associated with aggregate mining. While total dissolved solids doesn’t always pose direct health or environmental risk, measuring total dissolved solids can protect groundwater by serving as an indicator of other harmful contaminants. To better protect groundwater, we are proposing quarterly monitoring for total dissolved solids at sand and gravel operations that discharge to sensitive groundwater areas.
We want to hear from you
We are accepting public comment on the draft permit from 9 a.m. on Aug. 6, 2025 through 11:59 p.m. on Sept. 25, 2025. The draft permit, fact sheet, and other materials are available on our permit webpage. There are multiple opportunities to learn more about the draft permit, each with question-and-answer sessions, and opportunity to provide testimony. The details for the meetings are below.
- Online public meeting & hearing
Sept. 9, 2025 – 1:30 p.m.
Register online - Online public Meeting and Hearing
Sept. 10, 2025 – 5:30 p.m
Register online