Water is on most Austin-area residents minds these days. With decreasing supply due to drought, increasing demand due to population growth in the area, and rising rates for water due to over-burdened water utilities, we face a formidable task to assure that we will be able to access reasonable amounts of water moving forward.
Many interested parties are looking at what can be done to conserve water, and one of the most obvious areas in which many folks can conserve is in the irrigation of their landscapes. Some estimates put the quantity of water used for landscape irrigation in the hotter months in central Texas above sixty percent of total water usage. The City of Austin is implementing some programs to help homeowners/ responsible parties look for sources of water waste. But with limited resources, current programs do not make a very large dent in the problem.
In some discussions with a certain water conservation/education group recently, E.S.C. staff compiled some notes and ideas which we felt might be of interest to anyone interested in cutting their water bill, or simply doing their part to conserve our most precious natural resource.
From the irrigation side of the landscape equation, one of the most important things the homeowner can do is interact with the system. Interaction starts with actually watching the system run. Many owners never see their system while it is operating because it operates either very early in the morning, or very late at night. They simply take for-granted that all is well. Actually inspecting the system can reveal all kinds of info about the system… broken heads, broken pipes, heads spraying where they should not, heads flooding areas, etc. We’ve all seen the patterns in poorly irrigated areas…dry patches, dry circles/arcs in turf, and areas where there seems to be excessive growth are all signs of water issues. Investigation of your irrigation system is the first step in saving water.
The first thing a homeowner can check is the water meter. It is usually located near the street, in close proximity to your property line. Open the meter box, then lift the hinged lid on the meter and you should see a glass covered, numbered dial. There will also be a small red triangle, or some other sort of indicator which spins when water is passing through the meter. You can verify the moving part by turning on a hose bibb or a faucet in the house. When all water is shut off, the indicator will not be moving. As soon as any water is turned on, either in the house or in the irrigation system, the indicator will start to spin. A spinning indicator when all faucets, etc. are turned off is often an indication of a leak somewhere. If the indicator is spinning when all faucets and other valves are “off”, the next step would be to isolate the irrigation system from the residence or building to determine if the irrigation system is leaking or something in the home. To do this locate the backflow device or isolation valve for the irrigation system and shut it off. If the indicator still spins, the problem is on the “house side”. If not, reopen the valve you shut off and if the indicator starts spinning again, there is a leak in the irrigation system.
If it is on the irrigation side, the usual culprit is a broken mainline or a leaking valve. Valves can get debris in them and be unable to close completely. Or they can simply wear out over time. As for the mainline, it is the piping in the system which is under constant pressure, so a break there will be a constant loss. Even a small crack/break in a pressurized line can add up to significant loss over time. A large leak can add hundreds, even thousands of dollars to a monthly water bill. Often when a mainline is leaking, there is no visible sign of water. The pipe is buried and the water simply goes down into the ground. So the only way to check for leaks in mains is to do the meter test.
Now a broken sprinkler head may seem to be a pretty straightforward problem, which is often left un-repaired for long periods, but that one head can wreak havoc in less obvious ways. Not only is there a water loss greater than the amount of water normally sprayed by the head, but by lowering the pressure and flow at other heads on the same circuit, areas which would otherwise be sufficiently irrigated, suddenly are coming up short as well. An irrigation circuit is not a zero-sum entity. A problem anywhere on the circuit affects the whole circuit adversely. By going out and observing the system while it is running, you can see if water is gurgling out near a head, or where a head should be. Oftentimes I find heads which have been broken off by large mowers or some other activity simply laying in the landscape near where they should be connected. Sometimes they can simply be screwed back on, other times a little plumbing repair is required.
The irrigation controller is a place where significant water savings can be realized. When all the rest of the system is in perfect working order, we often find that the station run times are just too long. Many irrigators operate under the idea that you program spray stations at 30 minutes each, and rotary stations at 45 minutes each. Their philosophy is that if everything is soaked, and there are no dead plants (from under-watering), their client will be happy. Most irrigation systems are set with station run times which apply way too much water per cycle. That was fine when water was not scarce and expensive, but today a bit more thought needs to be put into run times. The other reason many irrigators go with their set run times is that they have no, or limited knowledge of the needs of the plants they are watering. This is very common, indeed I have heard more than a few say that the “irrigation system” is the reason to plant plants. I heard one say in a class once, “I designed a beautiful system, and then the darn landscaper wanted to plant a tree right where my mainline was”. Pretty backward perspective to be sure.
But while observing your plants, you can often slowly dial back the run times of some, even all of your stations until you begin to see stress in the plants. For example, say you have a system with 10 stations that each put out 15 gallons per minute. The run times are thirty minutes each. So each time the system runs, 4500 gallons of water are used. If you were able to dial each station back 5 minutes, you would use 750 gallons less each time you ran the system. The amount of time reduction you can achieve without detrimental effects will vary widely, but a methodical approach can yield serious water savings without harm to the landscape. Indeed, the landscape can become healthier over time, and more able to withstand tough conditions. Begin by dialing the run times back a couple of minutes at a time. Don’t go in and immediately cut the times by half, or some other extreme. Move slowly, incrementally, and you might just save some water, and money.