Yard Smart - Types of Projects

About: Rain gardens are bowl-shaped gardens designed to collect and filter water from your roof, driveway, or patio. Rain gardens can be shaped and sized to fit your yard, are filled with a rich layer of mulch and compost to help water soak in, and are landscaped with a variety of plants that fit your yard, sun, and soil. 

A rain garden will reduce water pollution, replenish the groundwater supply and provide a self-irrigating landscape. By slowing down rainwater runoff and filtering pollution, it helps protect our local creeks and reduces flooding in our neighborhoods. It also provides great habitat for birds and butterflies. 

Eligibility Criteria:

• Your property must be currently connected to the City stormwater drainage system.
• The rain garden must collect runoff from a minimum of 400 square feet of impervious surface area (800 sf for commercial, institutional, and industrial properties) being disconnected from the stormwater system.
• All other technical project requirements are listed in the Project Approval (LINK) packet.

Considerations: 

• Your property needs a fairly level yard with a slope less than 5%
• Rain gardens need to be located at least 10 feet away from your foundation and at least 50 feet away from steep slopes. 
• Rain gardens need well-draining soil. An soil drainage test will determine if a rain garden is right for your property.  

Resources:

• Rain Garden Fact Sheet(PDF, 4MB)
• Western Washington Rain Garden Handbook
• How to Conduct a Soil Drainage Test(PDF, 212KB)

About: A cistern is a large rain barrel that collects hundreds to thousands of gallons of water. Made of durable materials like metal, heavy plastic, or fiberglass, cisterns fill with water from your roof, gutters, and downspouts. Cisterns can help slow the flow of rainwater that floods our neighborhoods and creeks, and provide you with water to irrigate your lawn and garden each summer!

Eligibility: Cisterns must drain a minimum roof area of 400 square feet for single-family residential properties, or 800 square feet for multi-family, commercial, and industrial properties. 

Considerations:

• Cistern overflow must discharge at least 5 feet from the house foundation. 
• Cisterns must be placed at least 5 feet from property lines. 
• Full cisterns can weigh thousands of pounds. Careful placement and a sturdy foundation will keep your cistern safe and secure. 
• Dark colored cisterns in shaded locations will limit algae growth, reduce maintenance needs, and prolong the life of your cistern. 

Resources:

• Kirkland Cistern Fact Sheet(PDF, 9MB)
• DIY Cistern Installation Guide from Seattle Public Utilities. 
• Cistern Maintenance Guide(PDF, 2MB)
• Cistern and rain barrel sources
• Using Cistern/Roof Water for Edible Vegetable Gardens

About: Native landscaping is the removal some of your less permeable surfaces – such as patios or lawns - and replacing them with native plants and cultivars that have deeper root systems and amended soils. Native landscaping requires less water and maintenance, and is more capable of absorbing rainwater runoff. 

Eligibility: 

• Must receive runoff from 400 square feet (800 square feet for commercial) of impervious area.
• Must be at least 50% Pacific Northwest native plants by plant count. 

Considerations:

• New and young plants need water to grow strong roots. Watering is essential during the first two to three summers after native landscaping installation. 

Resources:

• DIY Native Landscaping Guide(PDF, 6MB)
• Native Landscaping Maintenance Guide(PDF, 7MB)
• King County Native Plant Finder

What? Many downspouts connect our roof gutters to underground pipes that carry water to our local creeks and Lake Washington. Disconnecting your downspout from existing standpipes can be accomplished fairly easily with an elbow, pipe extension, and splash block.

Considerations: 

• Disconnect no more than 700 square feet of roof area to a single downspout or splash-block. 
• Downspouts should not be disconnected within 50 feet of steep slopes or landslide hazard areas. 
• Downspouts should discharge at least 5 feet from your house foundation. 

Resources:

• DIY Downspout Disconnection Guide(PDF, 4MB)