What is the Neighborhood Drainage Assistance Program?

The Neighborhood Drainage Assistance Program (NDAP) resolves stormwater related flooding, erosion, and sedimentation problems on private property in unincorporated King County. The NDAP can design and fund projects to build new drainage systems or repair existing drainage systems. Technical assistance is also available for questions about construction, permitting, and storm drainage.

What types of problems receive assistance?

The NDAP targets problems beyond the control of private home and business owners. For example, nearby activities may change how stormwater impacts a property, older drainage systems may have reached the end of their service life, or emergency actions may be needed to restore emergency access to a property or prevent future, significant damage.

What kind of services does NDAP offer?

• New drainage system construction projects
• Drainage system repair through one-time, non-routine maintenance
• Technical assistance to help a property owner with addressing the problem themselves

What kind of problems won't the NDAP help with?

• Problems caused in part by the affected property owner
• Problems caused primarily by groundwater
• Drainage problems involving a neighbor's runoff
• The NDAP prioritizes projects based on the frequency and severity of damage caused. Because of this, minor problems where little damage occurs, or damage from very large, infrequent storms are less likely to receive funding. But, technical assistance may be available for these problems.

How can the NDAP help you?

• Call us at 206-477-4811 to discuss your concerns. We can schedule a site visit to determine if the problem qualifies for NDAP.
• Submit an online request to the start the process to determine if the problem qualifies for NDAP.

How are problems prioritized?

Because of the large number of eligible problems and a limited budget, we are not able to fund every problem. Potential projects are prioritized using a Benefit/Cost ratio. The benefit is based on what is impacted (e.g., landscaped areas, septic systems, access roads) and how often those areas are impacted (e.g., every year, once every five years). The simplified cost estimate for a potential project allows prioritizations from different years to be fairly compared but does not necessary reflect the current, actual cost of the entire project.

After reviewing the problem, our engineers will discuss possible solutions with the property owner and prioritize the solution chosen by the property owner.

What if no funds are available for your potential project?

If funds are not available for your potential project:

• You can be added to a wait list for consideration when funding is available;
• We can provide a list of engineers and/or maintenance vendors that can help you address the problem;
• We can provide technical assistance to help you correct the problem yourself; and
• We can provide standard construction details for common drainage facilities.

Call us at 206-477-4811 ask for an NDAP evaluation.

How can you help?

Keep track of drainage problems. Take pictures or videos. Make notes about what you have seen and heard during a problem. Take note of what you have done to try and fix it, and who you have talked to about it. Include the date and time of day with all notes, photos, and videos.

Document the problem on the ground. Stake the edges of high water in your yard, and mark the height of flooding on your buildings, fences, or tree. This will help our drainage investigators later.

More information

Report drainage, flooding, and water quality problems in unincorporated King County through our online report form.