Whatcom County, WA Landscaping Rules: Rainwater Harvesting (2026)
Key Facts
- Credit amount
- 10% of annual stormwater fee
- Eligible buildings
- new or remodeled commercial only
- State authority
- RCW 36.89.080
- Service area
- Lake Whatcom Stormwater Utility
- Request deadline
- 30 days of bill date
- Appeal deadline
- 30 days of manager decision
Summary
Inside the Lake Whatcom Stormwater Utility Service Area, a new or remodeled commercial building gets a 10% credit off its annual stormwater fee for installing a permissive rainwater harvesting system sized to the building's available roof surface, per WCC § 16.30.080(B)(5).
5. The parcel contains a new or remodeled commercial building that utilizes a permissive rainwater harvesting system that is properly sized to utilize the available roof surface of the building; or a. For qualifying permissive rainwater harvesting systems as provided for under RCW 36.89.080 and eligible under subsection (B)(4) of this section the formula is expressed mathematically as follows: A = F x 10% Where: A = The credit amount to be subtracted from the annual fee; and F = The total fee without credit.
Full Breakdown
Whatcom County created the Lake Whatcom Stormwater Utility Service Area under RCW 36.89 (WCC § 16.30.010) and bills an annual per-parcel stormwater rate based on equivalent service units (ESUs) tied to impervious surface (WCC § 16.30.060). Within that service area, WCC § 16.30.080(B)(5) lets a parcel with a new or remodeled commercial building qualify for a fee credit if it uses a permissive rainwater harvesting system properly sized to the building's available roof surface, as authorized under RCW 36.89.080. The credit is calculated as A = F x 10%, where F is the total annual fee without the credit and A is the amount subtracted from it.
This sits alongside a separate 35% credit for parcels built to the county's low-impact-development standard (WCC § 20.51.420) and a contiguous-parcel adjustment for same-owner single-family lots. To claim any credit, the property owner files a written service charge adjustment request with the public works manager within 30 days of the bill date (WCC § 16.30.080(A)); filing does not extend the payment deadline. The manager decides within 60 days based on submitted evidence, and the burden of proof rests on the owner. Adjustments apply only to the current and future bills, never retroactively (WCC § 16.30.080(C)-(D)).
Violations & Fines
There is no separate penalty for skipping the credit: a property simply pays the full unit-rate stormwater charge without the 10% reduction. A manager's denial of a rainwater-harvesting credit request becomes final unless the owner files a written appeal to the Whatcom County hearing examiner within 30 days of the decision (WCC § 16.30.080(E)). Unpaid stormwater charges (with or without credit) become delinquent after April 30 or October 31 and accrue 8% annual interest plus up to a 10% penalty under RCW 36.94.150 (WCC § 16.30.070, § 16.30.110).
Frequently Asked Questions
Does installing a rainwater harvesting system lower my Whatcom County stormwater bill?
Can a single-family homeowner get the rainwater harvesting credit?
How do I apply for the credit and what if it's denied?
Sources & Official References
Other rules in Whatcom County
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