Does a recycled water irrigation system sound strange to you? When you think about it, almost all of the water we use is recycled in some way. To make our tap water, water treatment plants take in previously used water. They filter and treat that water in order to make it potable. Most of us use that potable water to care for our lawns and gardens, but we don’t have to.

Plants don’t need water to be as clean as we do, after all, plants are used to rain water. So, we can use “recycled” water to meet our landscaping needs. This water is still treated by the city, just not to the same standards required for potable water. While you can’t drink recycled water, it’s perfectly safe to walk on a lawn that has just been watered with it.

The Basics of Recycled Water

Using a recycled water irrigation system will reduce the cost of your water and help you abide by water restrictions without sacrificing a green lawn or a lush garden. In turn, the city has to produce less potable water to it’s residents, which saves it money and keeps our potable water levels high for when we need it.

You may think the biggest savings from recycled water would be from the commercial recycled water systems that help greenhouses and farmers meet their water needs with a lower budget. However, homeowners can make a big impact with recycled water too.

The EPA estimates that a third of all residential water is used to irrigate our lawns and gardens. Reducing your water use for irrigation can increase how much fresh water is available in your city, and decrease the amount of water used in your city overall.

Those are the basic benefits of choosing to switch to a recycled water irrigation system, but there are drawbacks too. What should you consider when making your decision?

Local Laws

In your recycled water system, you can use your own grey water (water previously used to wash your hands or shower in) or you can use recycled water that your city delivers to you, which it also sanitizes for you. Either way, you’ll need to be sure your system is legal. Some cities do not allow recycled water systems, usually because their plumbing can’t effectively handle it. Other cities encourage it.

Incentive Programs

Many cities and organizations, especially those in the West, have seen the benefits of using recycled water for irrigation. They often offer incentive programs to encourage homeowners to invest in recycled water irrigation systems. This might be lower cost on recycled water, or a tax rebate on a portion of the costs of your system.

For example, Colorado has more than a dozen water recycling programs, and each offers recycled water at cheaper rates than potable water. Many Colorado water utilities offer rebates on irrigation equipment, which may apply to your recycled water irrigation system. A quick search on your public utility’s website should show you which rebates are available.

Recycled Water Pipes

Recycled water pipes are purple, so that plumbers, water treatment technicians, and homeowners won’t mistake the lines for potable water lines and cause contamination issues. Your city may already have these special pipes running near you. If not, and you plan to use the grey water you produce in your home, it’s best to use these specialty pipes for the purpose. There may be legal requirements around this, and your sprinkler technician should be able to inform you of what you’ll need to do to stay within the law.

Options for Algae Control

Recycled water is nutrient rich. It will bring more minerals and salts to your landscaping than usual. While this can be a great benefits to the plants you’re trying to grow, it can also create ideal conditions for algae growth in your ponds or pools. You likely already use an algaecide to control its growth in your pool. If so, you’ll need to use more of it.

Do You Need to Switch Soaps?

You may have heard that you need to switch soaps to use recycled water. If you’re using a greywater system that recycles the water you’ve already used to shower or wash your hands, it’s true. You’ll need to choose new non-toxic soaps and shampoos. Otherwise, the chemicals and salts you put into the water could harm your plants.

However, this isn’t true for recycled water. One of the benefits of connecting to your city’s recycled water line instead of using your own greywater system is that you don’t have to switch soap at all. The city’s water treatment plant will ensure your recycled water is healthy for your plants. That is, with one exception.

Do You Have Evergreens?

Most plants can thrive on recycled water just as they would on rain water. However, recycled water can effect some species of evergreen trees, over the long term.

Recycled water tends to have a higher salt content than potable water. Overtime, this salt collects in the soil and begins to effect salt-sensitive plants like some evergreen varieties.

The city and county of Denver released a report in 2017, revealing the condition of the trees in parks that used recycled water irrigation systems for the previous four years. While most trees were still healthy, some were beginning to show signs of poor health. The species that appear to be particularly vulnerable, according to that report, include:

  • Blue Spruce
  • White Fir
  • Linden Tree

Not all of the individual trees of these species were negatively effected by the recycled water. The only tree to perish was quite close to the source of the salt water, and in a ditch, such that it was over run with salt. Most others are doing just fine.

Further, since this issue has come to light, most cities attempt to reduce the salt content of their recycled water to avoid this problem. It’s also to increase the longevity of the pipes that deliver the water because salt can be harsh on them too. However, if you have a special attachment to an evergreen tree, you may not want to risk using recycled water to care for it.

The Costs of a Recycled Water Irrigation System

Recycled water irrigation systems are slightly more expensive than other irrigation systems. However, they make up for it over the long term because recycled water is less expensive per drop than potable water. If you can afford the upfront cost, or if you have the credit to finance it, the system can save you money in the long run. Plus, it’s reassuring to know your landscaping decisions aren’t impacting the availability to fresh water for your neighbours.