City of Spokane Valley

The City of Spokane Valley has enacted stormwater ordinances and a stormwater utility fee in order to comply with local and federal regulations and also to manage stormwater in a responsible and sustainable manner. The Stormwater Utility exists to maintain and improve City-owned drainage systems and natural drainage ways that flow in or through the City.  The City owns over 14,000 drainage structures that serve mainly the City-owned public road system.  Private property owners are responsible for the maintenance and care of their on-site drainage systems.  The State of Washington Department of Ecology and the U.S. EPA regulate all systems.


Stormwater Utility Rate for Commercial Properties

The stormwater utility fee divides stormwater fees among owners of developed properties. The fee is higher for property with greater impervious surface area since this property tends to contribute more stormwater loading on our public drainage systems.

That way, each property owner only pays for the estimated demand that each property would place on the stormwater system. Although the fee is a cost to property owners, it is not a tax on the value of the property.

Commercial property owners pay $21 per year for every 3,160 square feet of impervious surface on their property.

Impervious surface means a hard surface area, which either prevents or retards the entry of water into the soil mantle as under natural conditions prior to development, and/or a hard surface area which causes water to run off the surface in greater quantities or at an increased rate of flow different than the natural conditions prior to development. Common impervious surfaces include, but are not limited to, rooftops, walkways, patios, driveways, paved parking lots or storage areas, concrete or asphalt paving, gravel roads, packed earthen materials, and oiled surfaces which similarly impede the natural infiltration of stormwater.

Spokane Regional Stormwater Manual.


The regulatory threshold is the “trigger” for requiring compliance with the Basic Requirements of this Manual. This threshold varies from jurisdiction to jurisdiction. In Spokane County and the City of Spokane Valley, it is defined as “the addition or replacement of 5,000 square feet or more of impervious surfaces or the disturbance of 1 acre or more.” In the City of Spokane, the threshold is defined as “the addition or replacement of any impervious surfaces.” The regulatory threshold applies to the total impervious area replaced or added at full build-out. Refer to “common plan of development or sale” definition to determine whether your project will trigger the regulatory threshold.

All projects proposing underground injection control (UIC) facilities must comply with UIC requirements, regardless of whether they trigger the regulatory threshold.



To ensure that stormwater control facilities are adequately maintained and properly operated, documentation describing the applicable preventive maintenance and recommended maintenance schedule shall be prepared and provided to the entity responsible for maintaining the stormwater system.

For drainage ponds and other drainage facilities outside of the public road right of way, the project proponent shall provide the financial means and arrangements for the perpetual maintenance of the drainage facilities.

Proponents shall operate and maintain the facilities in accordance with an operation and maintenance plan that meets the criteria specified in Chapter 11. The operation and maintenance plan shall also include applicable source control BMPs, as described in Chapter 10.


All projects that meet the regulatory threshold and that propose drainage facilities or structures shall comply with this Basic Requirement. All projects that propose UIC facilities also must comply with the operation and maintenance requirements, regardless of whether they exceed the regulatory threshold.



Insufficient maintenance of stormwater control facilities can lead to poor performance, shortened life, increased maintenance and replacement costs, and property damage.

The local jurisdiction maintains the stormwater system structures located within the public road right of way and structures located within border easements that serve public road runoff, unless a separate agreement exists whereby the homeowner, property owner or other independent entity is responsible for the maintenance. Drainage tracts created by public projects will be maintained by the local jurisdiction. The project proponent is to provide for the perpetual maintenance of all elements of the stormwater system located outside the public right of way. The high-frequency maintenance of vegetated cover, turf grass and other landscaping within the public right of way and within border easements that accommodate public road runoff is the responsibility of the adjacent property owner. When applicable, the following maintenance-related items shall be submitted with the Drainage Submittal (refer to Chapter 3) for all projects:

• A copy of the conditions, covenants and restrictions (CC&Rs) for the homeowners’ association (HOA) in charge of operating and maintaining all elements of the stormwater system;

• A Financial Plan outlining the funding mechanism for the operation, maintenance, repair, and replacement of the private stormwater system, including contingencies; and,

• An Operations and Maintenance (O&M) Manual.

Appendix 5A and 6A of the Stormwater Management Manual for Eastern Washington outline facility maintenance recommendations and frequencies.


All projects that meet the regulatory threshold and that propose drainage facilities or structures shall comply with the Basic Requirement for operation and maintenance. All projects that propose UIC facilities also must comply with the operation and maintenance requirements, regardless of whether they meet the regulatory threshold.


For privately maintained stormwater systems in residential neighborhoods, a homeowner’s association, or alternate entity acceptable to the local jurisdiction, shall be formed to maintain the facilities located outside of the public right of way.

A draft copy of the CC&Rs for the HOA in charge of operating and maintaining the facilities associated with the stormwater system shall be submitted as part of the Drainage Submittal review package. The CC&Rs shall summarize the maintenance and fiscal responsibilities of the HOA, reference the O&M Manual (Section 11.1.4), and include a copy of the sinking fund calculations and Financial Plan (Section 11.1.5). Annual HOA dues shall provide funding for the annual operation and maintenance of all facilities associated with the stormwater system and for the eventual replacement of these facilities.

For commercial/industrial and multi-family residential developments with joint stormwater systems and multiple owners, a property owners’ association (POA) or similar entity such as a business shall be formed, or a reciprocal-use agreement executed.

Homeowners’ associations and property owners’ associations are to be non-profit organizations accepted by the Washington Secretary of State. A standard business license is not acceptable for this purpose.


For stormwater systems operated and maintained by a HOA or POA, an O&M Manual is required. The O&M Manual summarizes the tasks required to ensure the proper operation of all facilities associated with the stormwater system and must include, as a minimum:

• Description of the entity responsible for the perpetual maintenance of all facilities associated with the stormwater system, including legal means of successorship;

• Description of maintenance tasks to be performed and their frequency;

• A list of the expected design life and replacement schedule of each component of the stormwater system;

• A general site plan (drawn to scale) showing the overall layout of the site and all the facilities associated with the stormwater system; and,

• A description of the source control BMPs.


Stormwater Management Manual for Eastern Washington

Appendix 5A Maintenance Criteria
  • No. 1 – Wetponds
  • No. 2 – Bio-infiltration/Infiltration Trenches/Basins
  • No. 3 – Closed Treatment Systems (Tanks/Vaults)
  • No. 4 – Control Structure/Flow Restrictor for Wetponds
  • No. 5 – Catch Basins
  • No. 6 – Debris Barriers (e.g., Trash Racks)
  • No. 7 – Energy Dissipators
  • No. 8 – Biofiltration Swale
  • No. 9 – Vegetated Filter Strip
  • No. 10 – Wetvaults
  • No. 11 – Sand Filters (above-ground/open)
  • No. 12 –Sand Filters (below-ground/enclosed)
  • No. 13 – Media Filter
  • No. 14 – Baffle Oil/Water Separators (API Type)
  • No. 15 – Coalescing Plate Oil/Water Separators
  • No. 16 – Catch Basin Inserts
Appendix 6A Maintenance Criteria
  • Detention Ponds
  • Detention Vaults/Tanks
  • Control Structures
  • Drywells
  • Infiltration Ponds
  • Evaporation Ponds