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Drinking Water Requirements for Building Permits
If you are planning to add an accessory dwelling unit, a building permit cannot be issued by Planning and Development Services until Snohomish County Health Department verifies that you will be able to:
- Have adequate and potable water for the accessory dwelling unit (in other words, enough safe drinking water)
- Properly treat all the wastewater that could be produced
Depending on your current situation, there are different steps to take to meet the drinking water requirement. The three possible scenarios are listed below. For information that covers both wastewater and drinking water requirements for accessory dwelling units, a printable info sheet is available.
IF YOU ARE ALREADY CONNECTED TO A PUBLIC WATER SUPPLY
Contact your water provider to request a letter that states their ability and willingness to provide water to the attached dwelling unit. Submit the letter to the Health Department, and you're done! (You can submit this letter by email to SHD-EHQ@snoco.org, by mail, or in person at the front counter.)
IF YOU ARE DRILLING A NEW PRIVATE WELL
See our Well Site Applications and Review page for all the steps you'll need to take.
IF YOU HAVE AN EXISTING PRIVATE WELL
All three of the forms below must be on file with the Health Department before a building permit can be issued. Check with us first to see if we have any of these on file already!
Approved "Application for Individual Well Site Inspection"
This is to verify your well is in a suitable location. If it's not already on file, submit a new well site application and pay the fee.
Accepted "Request for Review - Individual Water Supply"
This is to verify that your well was constructed according to state code, provides water that is safe to drink, and can provide enough water to both connections (has a documented well yield of at least 400 gallons/day per residential connection or 800 gallons total).
If it's not already on file, submit a new Request for Review form. With it, you will need to submit a well log/report and lab results for water samples that have been tested for the contaminants listed on the form. If you do not already have this info handy, note that there are costs to having your well water tested or paying a well driller to complete a new well log.
- Searching for Well Logs/Well Reports: You can use Department of Ecology's Well Report Viewer to search for a well log for your existing well, or contact them for further assistance.
- Water testing: Use the searchable map maintained by the Department of Ecology to find a lab that tests drinking water if you need to have yours tested.
Declaration of Covenant for a Two-Connection Well
This is a legal document to describe property restrictions related to the well. We have a declaration of covenant example for a two-connection well to use as reference. Have the declaration of covenant notarized and then record it with the county Recording Office. There is a fee to have it recorded. Feel free to check with us first to make sure your declaration of covenant is complete and correct before having it recorded.
PLEASE NOTE: If the Well Site Application or Request for Review can't be approved/accepted because your well doesn't meet requirements, you'll need to either drill a new well to serve the attached dwelling unit or connect to public water, if possible.