Surface Water Management Division

Interactive Data

Hydrology Data including stream-flow collected every 15 minutes to 2 hours from streams and rivers around the county 

Geographic search for countywide water quality data 

Water Quality Data from streams and rivers around the county

Lake Quality Data from lakes around the county 

Groundwater Data - search by geography

Groundwater Quality and Well Data

Drainage Inventory Maps - search by geography

Real-time Flood Warning Information for Snohomish County rivers. Updated every 15 minutes.

The Fine Print

This website contains downloadable materials produced by Snohomish County government in the course of its official duties. Snohomish County disclaims any warranty of merchantability or warranty of fitness of these materials for any particular purpose, either express or implied. No representation or warranty is made concerning the accuracy, currency, completeness or quality of data depicted. Any user of these materials assumes all responsibility for use thereof, and further agrees to hold Snohomish County harmless from and against any damage, loss, or liability arising from any use of the material.