Rule Authorized Injection Systems

Geothermal closed loop systems, dewatering injection systems, roof drains and some stormwater injection systems may qualify after DEQ review as rule authorized. For an injection system to qualify as "rule authorized", facilities must be registered, reviewed and found to have no impact on water quality and meet all other DEQ, state and federal requirements. The burden of proof is on the owner/operator of the injection system to prove you are in compliance with federal and state regulations. DEQ issues rule authorization letters to the owner giving each site a UIC number in the database and each injection system its own number specific to the site. Copies of each letter are also sent to the city/county authorities and site consultants.

A copy of the Rule Authorization letter is to be kept at the site of the UIC for inspections (local, state and federal). DEQ staff and the public can access he UIC database to determine if a site is registered and rule authorized, or call to see if a site has submitted registration forms and is in the review process. Injection systems not rule authorized are in violation of federal/state rules and are subject to fines, enforcement and third party lawsuits.

If an owner or operator of a system cannot provide the required registration data to determine if the system is "rule authorized", then they must either:

1. Close the injection system and find an alternative method of disposal;
2. Hook up, if available, to the locally municipal stormwater sewer;
3. Modify/update the existing system to meeting the Rule Authorization requirements; or
4. Apply for a DEQ Water Pollution Control Facilities (WPCF) permit (general or area wide)

Overview of Stormwater Injection Requirements

Basic requirements apply to all stormwater injections except roof drains. In order to meet basic requirements the owner/operator of the injection system must submit inventory and registration information prior to construction to DEQ for review to certify that:

• No other waste or discharge is mixed with the storm water
• Example: Roof runoff is not required by DEQ to be pre-treated. Parking lot run off is required to be pre-treated. If mixed the amount of water to be pre-treated doubles as does the cost to pre-treat and maintain the system.
• Storm water runoff is minimized and that no other disposal option is appropriate. If city hook ups are not available DEQ requires developers to consider the use of L.I.D.s or green options (e.g. see stormwater information design fact sheet).
• Example: see the City of Portland stormwater manual Hierarchy for pre-treatment.
• DEQ will call and verify with the city that the site cannot use any thing but a drywell. Drywells are the last option in most cases.
• No water supply wells are present within 500 feet (domestic, irrigation or industrial)
• No public drinking water supply wells are present within 500 feet or the within delineated 2 year time-of-travel, which ever is more protective.
• No soil or groundwater contamination is present.
• Verify the site is not on the cleanup list (ESCI) or profiler. Example: Site Y once was a gas station and is now proposed as a fast food site. The gas station has not been cleaned up so the site development is denied. Or if cleaned up has occurred, the drywells must be placed in a location away from the cleanup area (generally 50 ft) so as not to move any remaining contamination.
• If a site later becomes listed on ESCI; is found to be contaminated or contributing to local groundwater contamination, the UIC rule authorization will be revoked.
• The injection system is not deeper than 100 feet, does not discharge into groundwater or below highest seasonal groundwater level.
• Example: For bacterial protection DEQ requires a 10-foot vertical separation between the bottom of the drywell and the first perched seasonal high aquifer. Roof drains need 5 ft of separation.
• Drywells with wet feet (in the seasonal high water table) are a high contamination risk and are to be closed upon discovery or modified to meet requirements.
• A confinement barrier or filtration medium must be present, or pre-treatment must be used to prevent or treat storm water contamination.
• Not all parts of the state have soils capable of providing adequate percolation and attenuation (treatment) for stormwater disposal. Disposals at depth often circumnavigate the soils natural ability to treat stormwater, which is associated with the topsoil layers and the presence of organics. Pre-treatment is needed to deal with contaminants normally found in street/parking stormwater.
• The design and operation of the injection system is to prevent accidental or illicit disposal, and temporary blocking of the injection system is available.
• Example; a drywell located at a sites loading dock cannot meet this requirement. The drywell would either need to hook up to the city system or isolate the stormwater discharge from the potential spill area. To date 75% of sampled drywells at loading docks are contaminated and end up on the cleanup site list.

Note: EPA has stated that the use of oil/gas or oil/water separators does not constitute treatment to MCLs for stormwater since they only separate out the solids and floatables. These designs do not deal with the hydrocarbons, organics or bacteria associated with stormwater. In addition, testing of stormwater treatment designs, such as stormceptor has found that these systems do not provide adequate treatment for bacteria, dissolved metals and organics when discharged to groundwater. Swales and biofiltration have been found to be up to 85-95% effective in treating all the contaminants in stormwater and are protective of groundwater. DEQ by policy will approve the use of proprietary systems that have achieved ranking of conditional or general use from in the ground testing by the Washington Department of Ecology (see ecologys stormwater web page).

Essentially, common surface water treatments do not always perform adequately in dealing with groundwater pollution. Stormwater contamination is an event issue and is not based on annual rainfall. Systems need to be designed to deal with typical large event volumes and intensity not the return number of events.

Stormwater Category Requirements PDF (these apply to Rule Authorization Requirements)

Municipal owners with 50 or more injection systems are required to provide additional data due to the volume being discharged and the risk to groundwater quality and public health. Municipalities must submit registration inventory data 90 days prior to construction for new sites for approval by DEQ. The additional data is to include: an evaluation of the potential impacts to groundwater quality, certification that the systems are not exposed to toxics, and a written stormwater management plan. The stormwater management plan should include a stormwater systems assessment, systems controls (pretreatment, BMPS and source controls), injection spill prevention plan, maintenance plan, employee and public education, annual monitoring and record keeping. All existing and new injection systems must be able to meet the Rule Authorization (RA) requirements. If existing injection systems do not meet all the requirements, then regardless of the number of UICs owned, DEQ will require a state area wide permit.

Small municipal systems with under 50 injection systems will also need to submit registration inventory data 90 days prior to construction at new sites, certify that the stormwater is not exposed to hazardous substances, and submit a written stormwater management plan for DEQ approval. All existing injection systems must be able to meet the RA requirements. If the existing systems cannot meet all requirements then the city/county or state agency will need to apply for a permit regardless of the number of UICs owned.

Industrial and commercial facilities that handle hazardous substances, toxic materials and petroleum products will need to certify that stormwater is not exposed to hazardous substances, toxic materials and petroleum products. The certification shall include site assessment, location of the materials and stormwater discharge points, methods used to prevent exposure, sampling, site controls (pre-treatment, BMPs), spill prevention for injection systems, maintenance plan, information on past spills/releases, and submit a written stormwater management plan for DEQ approval.

Industrial and commercial facilities with no hazardous substances will need to certify non-exposure every five years and submit a written stormwater management plan.

Large parking lots (big box) and high traffic areas with 1000 or more vehicle trips per day will need to certify non-exposure to hazardous substances, submit a written stormwater management plan, site assessment, site controls, annual monitoring, and maintenance plan to DEQ for approval.

Small parking lots will need to certify non-exposure to hazardous materials and submit a written stormwater management plan.

Notification of Change of Status

Inventory information should be updated whenever a change occurs; for example, when a business changes ownership, when the injection system is proposed for closure, sealed up, its use discontinued or when the site is abandoned or remodeled to serve another use. Existing registered owners and operators of injection systems are required to notify DEQ Headquarters in writing of any changes to operational status of the injection system prior to use. DEQ can re-evaluate sites at this point in time to verify if the system is still protective of groundwater and allow or revoke the existing rule authorization.

Revocation of Rule Authorization

DEQ can revoke any rule authorization at a later date if the drywell(s) no longer comply with all requirements of rule authorization. Revocation will occur for example, if the owner fails to install the approved pretreatment system, or is later found to be too close to a water well or submitted falsified data. Sites approved and later found to be in need of cleanup will also be revoked.