On-going maintenance is essential to keep your RainWise installation working properly.

Seattle Public Utilities and King County are counting on your RainWise project to prevent polluted stormwater from going into our waterways. Your cistern and/or rain garden is made possible with public funds. In return, RainWise requires homeowners to maintain their RainWise project for five years.

Understand Your RainWise Commitment

Read the RainWise Homeowner Agreement, which customers sign before receiving a rebate.

Inform the next homeowner about RainWise. If you are selling your home which has a RainWise installation, please email us at Your RainWise project must be listed in your Seller’s Disclosure Form to let the next owner know about your cistern and/or rain garden.

Cistern Maintenance

Watch Cistern care video in (English, Spanish, Vietnamese).

Read Cistern maintenance guide in (English, Spanish, Vietnamese,Traditional ChineseCambodian).

How to install a pump to a cistern

For more information visit the Cistern maintenance page.

Rain Garden Maintenance

Watch instruction on weeding and mulching your rain garden (English, Spanish, Vietnamese).

Watch instruction on watering your rain garden (English, Spanish, Vietnamese).

Read a printable maintenance guide (English, Spanish, Vietnamese,Traditional ChineseCambodian).

For more details on maintaining rain gardens.


Not sure where to find arborists’ wood chips for fresh mulch?

Need help with rain garden plants and weeds?

Wondering how often or how long to water your new rain garden?

Contact the Garden Hotline at:

206-633-0224 or

Multi-lingual service is provided.

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