By now, you probably know that we usually tell you how much to water, in inches, when we service the lawn. We’d like to tell you exactly how long to water, but there are too many variables such as:
water pressure
type of heads
area watered per zone
Therefore any time to water would just be guesswork. Instead, here’s how to convert amount of water into minutes per zone:
Here’s how to calibrate:
First of all, be sure that your system is functioning properly. That means making sure all of the heads are working and there are no leaks either in the heads themselves or in the underground plumbing.
Set up either straight-sided cans (tuna or cat food cans work well) or rain gauge(s) under each zone.
Run your system as it is already set.
Measure the amount of water in each can or gauge. Do this very soon after watering so that there is no loss to evaporation. Either read your rain gauge(s), or put each can on a level surface and stick a ruler into it and see how much water is in it.
Adjust your watering times to deliver the amount of water that we recommend. For example, if you find that watering a zone for 20 minutes delivers 1/4” of water, and we recommend 1/2”, then set the zone to water for 40 minutes. Do that for each zone and you’ll have a good, working knowledge of your system.
Additional tips:
Check your system periodically (once as month, or so) to see that all the heads are OK and it’s still running properly. All it takes is one broken head to lessen the flow of water to the entire zone.
Get a smart controller for your system. I have a smart controller that allows me to totally control the system from my phone. It also has a water saver feature that will skip a cycle if rain is forecasted. That can be a very valuable feature if you live in a town with expensive water.
If you’re on a municipal water supply, and also use a municipal sewer system, it may make sense to get a “deduct” meter for your irrigation. Most municipalities charge a sewer fee based on your water usage, whether it goes into the sewer system or not. A deduct meter allows you to deduct the sewer charge for any water used through the outdoor water supply that the meter is plumbed into. The savings can be substantial!