How much water does your garden need? Get week-by-week watering information for your ZIP code. Sign up for a weekly text or email: regionalh2o.org/wwn.
It can be tough to know how much to water your lawn and garden. That’s why we work with our partners at the Regional Water Providers Consortium to give you the amount of water your lawn will need each week from April through September.
No lawn? No problem!
You can still use the Weekly Watering Number. Since lawns need the most water, the Weekly Watering Number is designed with grass in mind. But it’s easy to adjust for other plants:
- Shrubs and perennials: Water 50% of the recommendation
- Vegetables: Water 75% of the recommendation. New starts may require more water.
- Trees: Newly planted trees need regular watering for up to the first couple of years. Established trees may need a deep soak or two in summer.
How do I know how much I’m watering in inches?
The Weekly Watering Number is calculated in inches, but you probably want to know how long (in minutes) to water. To figure this out, all you need are a couple of tuna cans, a ruler, and a timer.
Learn how to measure your sprinkler system, soaker hose, or drip system output.
How is my Weekly Watering Number calculated?
The number you get is based on rain fall, evapotranspiration, and solar radiation data for your ZIP code. This weather data is used to estimate the amount of water your plants will need to replace what they have lost over the week.
For more outdoor water efficiency tips visit portlandoregon.gov/water/outdoor.