Watering Schedule for Week of 5/17-5/23 Please note: The Weekly Watering Schedule is a guide calculated to replenish the soil moisture lost last week. It is not a forecast; if unseasonably hot or wet weather is expected, please adjust if needed for your garden.
ETo 5/10-5/16	1.19
Rainfall 5/10-5/16	0.0
Percent Change from Prev. Week:	11.2%
WATERING INDEX	80%
Northern Zone
Category	Minutes
Spray System: Turf	42
Spray System: High Water Use Plants	31
Spray System: Low Water Use Plants	13
Drip System, High Water Use Plants	Minutes
1 ft. Canopy	17
2 ft. Canopy	68
3 ft. Canopy	153
Drip System, Low Water Use Plants	Minutes
1 ft. Canopy	7
2 ft. Canopy	29
3 ft. Canopy	66
Central Zone
Category	Minutes
Spray System: Turf	38
Spray System: High Water Use Plants	28
Spray System: Low Water Use Plants	12
Drip System, High Water Use Plants	Minutes
1 ft. Canopy	15
2 ft. Canopy	61
3 ft. Canopy	138
Drip System, Low Water Use Plants	Minutes
1 ft. Canopy	7
2 ft. Canopy	26
3 ft. Canopy	59
Southern Zone
Category	Minutes
Spray System: Turf	26
Spray System: High Water Use Plants	19
Spray System: Low Water Use Plants	8
Drip System, High Water Use Plants	Minutes
1 ft. Canopy	10
2 ft. Canopy	41
3 ft. Canopy	92
Drip System, Low Water Use Plants	Minutes
1 ft. Canopy	4
2 ft. Canopy	18
3 ft. Canopy	40

Many people turn on their irrigation systems full tilt as soon as the rainy season ends. But over the course of the summer, your plants’ water needs will vary a lot depending on weather conditions, day length and other factors. By adjusting your irrigation schedule weekly to give your plants just what they need, you’ll save water and money while maintaining a healthy garden.

How do I use the Weekly Watering Schedule?

First, find which of Marin’s three climate zones you live in. Then scroll down the table at right to find the appropriate runtimes based on your climate zone, irrigation system (spray or drip) and plant types.The runtimes are for a full seven-day period, so remember to divide the number of minutes by the number of days that you irrigate per week to get the watering minutes for each of your irrigation days. 

Note: The runtimes provided are based on a 2-inch-per-hour precipitation rate for spray irrigation systems, and 2-gallons-per-hour per plant application rate for drip irrigation systems. Your actual precipitation or application rates may vary. For information on how to determine your precipitation rate, click here.

Can MMWD send me a weekly reminder to adjust my irrigation schedule?

Yes! You can sign up to receive the schedule via email, along with helpful water-smart garden tips. Or, follow us on Twitter  and we will "tweet" you a reminder every Friday during irrigation season.

What is the “Watering Index”?

The Watering Index is a guide for people whose irrigation controllers include a water budget adjustment feature. This feature (either a button or a dial) eliminates the need to change the watering times one-by-one for each irrigation valve, and permits the watering run times for all valves to be increased or decreased with just one adjustment. Learn more about the Watering Index.

What is “ETo”?

ETo—or reference evapotranspiration—is the amount of water lost into the air through evaporation from soil and transpiration from plants. The watering schedules for any given week are calculated to replenish the soil moisture lost the previous week. Learn more about evapotranspiration.

How does MMWD determine the ETo?

MMWD employs three high-tech weather stations—one in each of the three different climate zones in Marin—to continuously monitor air temperature, humidity, rainfall, wind speed and solar radiation. This information is used to determine the rate of evapotranspiration.

• Water in the early morning when it’s cool and the wind is calm to reduce evaporation.
• Group plants with similar water needs together.
• Apply mulch to garden beds to slow evaporation of moisture from the soil.
• Fix irrigation leaks and adjust sprinkler heads so that they water plants, not pavement. Trim back vegetation where it blocks spray patterns.
• Install a rain shutoff device if you don’t have one.
• If you see misting, install a pressure reducer.
• Consider investing in a “smart” irrigation controller, which adjusts automatically to give your plants just the right amount of water.

Questions?

Contact the Water Conservation Department  at (415) 945-1520.