Certified Site Water Planner (CSWP)
Find out how much water your lawn needs in real time! Get irrigation requirements and see up-to-date weather data for your area from the Puget Sound Weather Stations.
ET (Evapotranspiration Rate) is how much water your plants use—thus, how much water you need to replace to keep your landscape green. Watering more than this is a waste of money and water.
Users who need access to weekly raw ET/rainfall data in CSV format can download the data by clicking here.
As with most technology, weather stations and the technology that ties it all together, are sometimes victims of malfunctions. Occasionally the weather data produced and posted on this site might be temporarily inaccurate. Please check the data being used for obvious errors. (for example: if the ET one day is .13" and the next it is 300" then caution is advised)