Trusted local news leader for Prescott area communities since 1882
Tue, Aug. 20

Rainwater harvesting reduces demand on existing water supply

Q: Our monsoon season will start in a few months and I want to conserve water and am thinking about installing a rainwater harvesting system. - Mike and Sue, Camp Verde

A: Did you know that the average roof (1,000 square feet) collects 600 gallons of water for every inch of rain? So let's not let all of that water go to waste! Rainwater harvesting systems provide distributed stormwater runoff containment while simultaneously storing water, which can be used for plant irrigation and other uses. There are two types of rainwater harvesting systems - active and passive.

The components of an active system are rain barrels, usually 50 to 100 gallons, and/ or cisterns of 100-gallon capacity plus. There are many potential uses for captured active rainwater, such as watering plants and washing cars. By "actively harvesting" rainwater, this means that you are collecting, storing and recycling water that would otherwise be sent to municipal sewer systems. Arizona Seamless Gutters on Sixth Street in Prescott is a wonderful resource for rain barrels and system collection and information.

It is relatively easy to get started with an active harvesting system because you just need to buy or make rain barrels out of a food-grade drum and a hose spigot. The rain barrel needs to be positioned under a roof downspout and when it rains - collection is underway. With an active system, you need to plan for overflow or make sure you direct the excess water to other outdoor vegetation areas. It is important to keep the rain barrels covered with screens to prevent mosquito breeding and other debris from entering the collection site.

Passive rainwater collection systems are made from berms, basins, rain gardens and swales that have been created in a yard. Passive systems rely on micro-topography to direct water toward depressions in the landscape where water will infiltrate the soil and benefit the landscape plants. Depending on the size of your yard and area for collection, you could achieve a far greater storage area because soil has more capacity than a tank. Water runoff from the roof and/or driveways would have to be directed to the ponding and retention area. In most cases, this would and should involve the work of a landscaper to ensure that the water is being captured correctly and that your plants can handle water inundation and also periods of dryness. These areas should also be landscaped so it looks like a natural part of the yard. If you are considering installing a passive rainwater collection system, it would be wise to obtain a soil test to determine whether the site is suitable for water collection.

Harvesting rainwater has been around of decades and going green is becoming increasingly popular and it is important to remember that small steps can make a huge difference. If you want to reduce demand on our existing water supply, reduce run-off, erosion and contamination of surface water, then try rainwater harvesting. Rainwater can be used for nearly any purpose that requires water. Rainwater is especially good for plants because it is free of salts and other minerals that harm root growth. As rainwater percolates into the soil, it forces salts down and away from root zones, allowing roots to grow better and making plants more drought-tolerant.

Here are some questions and brief answers that have come in this week as well pertaining to rainwater harvesting.

Is rainwater harvesting allowed in Yavapai County? Yes.

What is the purpose of rainwater harvesting? The purpose is to facilitate conservation of valuable water resources by accommodating the use of harvested rainwater. In Yavapai County, this use is intended for non-potable use only.

What are your thoughts about our municipalities considering and encouraging rainwater harvesting for irrigation and flushing? And should there be an incentive for the disconnection of residential downspouts from storm sewers?

What permits are required to install a rainwater harvesting System? None, for the collection of rainwater to use outside the house. There are no current applications for using rainwater for purposes like toilet flushing or potable water.

There are no written codes and/or requirements for dealing with potable water from rainwater harvesting systems. There are no cross connections allowed and rainwater cannot be run into the municipal water systems. There are no plumbing codes because potable water connections are not allowed. There are no written policies for using rainwater by maintaining standards for public health protection. There are no codes to define the means of piping arrangements to protect potable water from becoming contaminated. There are no codes for the purpose of supplying rainwater to hose bibs, water closets, urinals, domestic washers, irrigation, etc.

How do I calculate rainwater harvesting potential for my home?

Collection Area (sq. ft.) x Rainfall (in/yr) / 12(in/ft) = Cubic Feet of water/year

Cubic Feet/Year x 7.43 (gallons/cubic foot) = Gallons/Year

For example, a 500 sq. ft. roof that gets 36 in/yr will produce 1,500 cubic feet or 11,145 gallons of water per year.

What is involved with rainwater harvesting and a connection to plumbing fixtures?

• Adoption of a plumbing code change first and foremost

• A central storage component of the rainwater harvesting system, which involves protection and maintenance that is essential for the health of the system

• A screen or other device installed on the gutter or downspout system

• A piping system to convey the harvested rainwater and distribute it to the defined areas

• A pump or pressure system

Not to sell short the installation of a rainwater harvesting system that would allow connection to plumbing, but there are too many provisions to list to give as to exactly what is required to install a system that would allow the collection of potable water for home use. We have listed a few of the important ones above.

Remember to tune in to YCCA's Hammer Time twice each weekend Saturday and Sunday morning 7 a.m. on KQNA 1130 am/99.9 fm or the web Listen to Sandy and Mike talk about the construction industry and meet your local community partners and contractors.

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