Smart Irrigation

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Smart Irrigation (ET) Controllers

In Portola Valley, 70% of our water is used for landscaping.  Smart Irrigation Controllers that have been set up properly can yield up to a 30% reduction in outdoor water use while supporting healthy plants. This is the biggest breakthrough for landscape water conservation since the introduction of drip irrigation over 30 years ago. Cal Water offers rebates of up to $125 to customers who install a smart irrigation controller.

Smart Controllers act like a thermostat for your irrigation system telling it when to turn on and off, using local weather and landscape conditions to tailor watering schedules to actual conditions on the site. Instead of irrigating using a controller with a clock and a preset schedule, Smart Controllers allow watering schedules to better match plants' water needs.

Potential water savings: For a typical PV Household with monthly average water consumption of 25 ccf with 70% going to landscaping, you could save up to $400/year by converting to a Smart Controller (depending on how frequently you have historically adjusted your sprinkler controller to match current weather conditions). And this does not include the $10 per CCF surcharge for going over your water budget. So if this helps you meet your water budget, your true savings could be significantly larger.

To learn more about how smart irrigation controllers work, click here.

For information on choosing a smart irrigation controller, click here.

 

 

Links to Additional Smart (ET) Controller Information:

 

Sprinkler Nozzles  

Spray sprinkler nozzles have traditionally been used for home irrigation systems. There are numerous newer approaches that provide better uniformity, with less water loss to evaporation and wind drift, while providing better water absorption.

For lawns, the use of efficient rotors and MP rotator nozzles allows for heavier water droplets that reach the grass instead of misting away into the atmosphere. Studies have shown that switching to high efficiency sprinkler nozzles can result in greater than 30% water savings. Cal Water offers up to 25 free Toro high efficiency sprinkler nozzles that can be used to easily replace existing inefficient spray nozzles.

For non-lawn areas, consider converting to drip irrigation. Drip irrigation systems can use 20 to 50% less water than conventional pop-up sprinkler systems.

Links to Additional Sprinkler Nozzle Information:

 

How Long Should I Water?

The Urban Farmer Store has published two excellent tables showing how to program your sprinkler controller depending on soil type, plant type, and water distribution technique. The information in both is the same, but you may find one or the other easier to use. The table provides the interval between watering days, the number of cycles to be run each watering day, and the length of each cycle. (These tables do not meet the current drought restriction to only run sprinklers twice per week.)

SFBay_Irrigation_Schedule1

SFBay Watering Guide

 

Here is a Lawn Sprinkler Schedule that does conform to the twice per week drought restrictions:

This is the schedule for summer irrigation for cold-season grass in silty clay soil for twice a week watering. The range is provided for watering from deficit to optimal levels. Set the timer to run two days a week according to your address. On each watering day, set the timer to run the number of cycles indicated for the number of minutes. Allow about 1 hour between cycles so the water can absorb into the PV clay soil. Deficit irrigation provides sufficient water to maintain adequate appearance with less growth. Note that cold-season grasses can survive and still provide soil cover with thinning if they receive about 60% ETo, which is 15% lower than the lowest cycle times given below. Note that to reduce your water use by 36% you will likely need to severely restrict your lawn irrigation to levels lower than indicated here or pay $10/CCF surcharges.


interval

cycles

min/cycle

Fixed Sprinklers (most common)

3.5 days

4 to 5

8

Rotors (efficient)

3.5

3 to 5

20

MP Rotators

3.5

3 to 5

23

 

Ideas for Saving Water on Landscaping 

An excellent class was held in Portola Valley in April 2015 on "Maintaining Existing Landscaping During a Drought". The links below point to the material from that class.

Here is a list of 10 ways to reduce lawn watering.

Here are numerous ideas for how to make your irrigation more efficient.


 

What if I Need Help?

If you would like to hire a professional to help with your irrigation needs, check out the Water Savvy list of professionals who have done work in Portola Valley.