Arizona has four main water sources – the Colorado River, other surface water such as lakes, rivers and streams, groundwater, and reclaimed water. All of these, however, are limited in nature.
The Colorado River serves as a water supply, not just for Arizona but also for the other Colorado River Basin states, including New Mexico, Colorado, California, Utah, Nevada, and Wyoming. The rights to use the water from the Colorado River are governed by the “Law of the River,” wherein it is stated that each year, Arizona gets 2.8 million acre-feet of water. This may seem enough, but not with the State’s growing population and the corresponding increase in water demand.
Given the state’s desert climate, the amount of water from surface water sources can vary throughout the year. The Arizona government has already constructed storage reservoirs and put systems to maximize water use from this kind of source. As of this date, rivers like the Agua Fria, San Pedro, Gila, Salt, and Verde have already been developed along with almost all other natural surface water in Arizona.
The population in Arizona also utilizes groundwater for their everyday use. About 43% of the population’s water use is sourced from groundwater, which has led to an overdraft since more water is pumped out before nature has the opportunity to replenish it. In a study conducted by Laura Condon and Reed Maxwell, it was found that the drying up of surface waters is connected with the abusive pumping of groundwater.
The last water source is the reclaimed water or effluent, which is wastewater. The wastewater is treated and filtered for specific uses only as it is no longer considered safe for human consumption.
Despite the existence of these four main water sources in the State, as long as there are natural occurrences beyond human control like drought and dry climate, growing population, high demand for water by both home and industry, without water conservation and other measures observed, Arizona will soon be depleted of its water resources. It is now facing water shortages of a high degree, and water access is becoming limited. Arizona is on the top of the list of states regarding water scarcity being high risk.
Residents and business owners will have to source water from elsewhere. The state must likewise secure additional water supplies or come up with ways to conserve and preserve the existing water sources. The most obvious and accessible choice would be rainwater.
According to the Arizona State Climate Office, Arizona’s average annual precipitation varies on its location within the State. In the southwest at Yuma, the average annual precipitation is around 3 inches, while in East-Central Arizona in the White Mountains, it could reach up to 40 inches. It’s a different story in the dry and desert Southwest region. With a population of 7,378,490 as of 2020, it is fortunate that it is legal to collect rainwater in the state. There are no laws, ordinances, or regulations against the act of rainwater harvesting. Otherwise, people living in Arizona would experience water shortages for a long period. Rainwater harvesting has helped in sustaining the state’s water supply.
Rainwater harvesting, which is also called rainwater collection or rainwater catchment, is the act of installing and using a catchment system that will enable one to collect rainwater, passively or actively, for storage, plumbing, cleaning, or direct outdoor use for landscaping or irrigation.
No federal laws regulate or prohibit rainwater harvesting. Hence, state regulations on rainwater harvesting vary widely from state to state. The Arizona State legislature had passed bills such as House Bill 2830 that proposed an energy and water savings account to fund related projects. Some of which eventually became laws regarding rainwater harvesting. Most of these laws cover definitions of terms related to rainwater collecting, period as to when it is allowed, areas where it is permissible, how rainwater should be collected or harvested, technical resources, limitations, restrictions, incentive or rebate programs, and other relevant information. Although some states in the country don’t have established regulations specifically encouraging or restricting rainwater harvesting or collection. Rainwater harvesting may seem like a simple and harmless concept, but when you consider public health, water rights, safety, and quality, it is only right and proper to have laws in place for rainwater collection.
Rainwater harvesting can either be passive or active. It is passive when rainwater is directed by the use of pipes, basins, and other tools, to one’s area, while the practice is considered active when one has a catchment area that collects the rainwater and then stored in a barrel, container or tank for later use.
As of 2019, Arizona has six (6) State Rainwater Harvesting Regulation Destination. The Department of Water Resources regulates these local laws, most of which provide incentives for installing rainwater harvesting systems, while some even provide funding for initial installation.
Here are some cities and counties in the state of Arizona that have laid down specific regulations, guidelines, and mandate regarding rainwater harvesting:
Tucson’s city was the first in the nation to adopt an ordinance that focuses on rainwater harvesting. Although, as previously mentioned, there are no laws in the state that prohibit rainwater harvesting, the second-largest city in the state with more than half a million residents deemed it proper to enforce laws regarding this matter together with water consumption, conservation, and regulation so that they will be continuously practiced, observed, and active for the long run.
The Tucson Rainwater Collection and Distribution Requirements or Ordinance 10597 but most popularly known as the Commercial Water Harvesting Ordinance, covers all commercial development and site plans non-residential focuses mainly on landscape water use. The ordinance was well thought out, considering that 45% of Tucson’s water use is intended for outdoor purposes.
Under the said ordinance, establishments must submit a rainwater harvesting plan with the site plan that shows its landscape water budget for all site landscaping and how half of the budget will come from collected rainwater. The landscape water budget shall be detailed and shall show the required water volume for the landscape annually. There shall also be an implementation plan that shows how the development plans to harvest rainwater and a metering system. Hence, commercial development and site shall submit the following requirements before starting with their project:
- Development Plan
- Rainwater Harvesting Plan
- Landscape Water Budget
- Implementation Plan in compliance with Development Standards
- Water Metering whether separate water meter or irrigation sub-meter
There will be a site inspection, and if the rainwater harvesting system passes the standard set forth by the city, only then will a certificate of occupancy be issued. The standards can be relaxed depending on the conditions, topography, soil, and ratio of the entire site’s landscape area as long as the ordinance’s purpose is reached. Establishments that fail to meet the standard will be fined, and the owner will have to submit an annual report stating the total rainwater collected, water use data, and meter data. Any condition in any contract, agreement, or deed that prohibits rainwater harvesting is invalid and cannot be enforced by any party.
All new commercial development shall comply with the mandate that 50% of the landscape water budget shall come from the rainwater harvested on the site. Strict compliance shall only be observed if the annual precipitation is equal to or greater than that determined in the development standard.
Owners or their successors may apply for a revision of the rainwater harvesting plan to the Director of Development Services within three (3) years from the issuance of the certificate of occupancy due to the following reasons:
- There was a mathematical or engineering error concerning the amount of water needed for the site landscaping.
- There were changes made to the landscape after which would affect the previously submitted landscape water budget.
- The discovery of other factors and additional data would subject the water budget and rainwater harvesting plan to changes.
There are also exceptions to the general 50% rainwater harvesting requirement. Developments with portions designated to the following uses are exempted from complying with the said rule:
- Botanical gardens
- Public parks
- Crop production
- Both public and private outdoor recreation facilities that are intended for public, school, or daycare center use
- Other natural open spaces
The Commercial Water Harvesting Ordinance secures water supply for the longer term and addresses the foreseeable drought in the Southwest area. It is also meant to reduce potable water use when non-potable water such as rainwater can be utilized instead. It will be saving the city money when it comes to development and reduces the demand for potable water supplied by the city.
In Tucson, the local government provides incentives for homes that observe rainwater harvesting, whether passive or active, through a rebate program. The Tucson Water Rainwater Harvesting Rebate Program provides a reimbursement of up to $2,000 for installed rainwater harvesting systems in residential buildings. Passive rainwater harvesting, including rain gardens that source rainwater from the street, entitles one up to a $500 rebate. The Metropolitan Domestic Water Improvement District’s Conservation Rebate Program also reimburses $200 to their customers who have rainwater harvesting systems on top of the above-stated rebates. According to Tucson’s Water Conservation Report, it is because of these rebate programs that the city saved 52.1 million gallons of water!
As of May 1, 2020, a fee called the monthly Green Stormwater Infrastructure Fee had been charged to residents of the city at the rate of 13 cents for every 748 gallons of potable water used. The funds raised from it will be used for projects that will include installations of stormwater capture systems.
The city of Flagstaff has passed Ordinance 2012-03 or more known as the Flagstaff Rainwater Harvesting Ordinance. The said ordinance has set rainwater harvesting requirements in line with the Stormwater Management Design Manual. It addresses the problem of drought and provides solutions and alternatives for water supply. It also emphasizes the benefits of active rainwater harvesting, such as reducing water volume in the city’s stormwater conveyance system and reducing portable and reclaimed water use to water plants and for irrigation purposes.
The Low Impact Development (LID) introduced by the city is a system wherein stormwater is contained and reused after contaminants, and other pollutants are removed. This is required to be constructed for all new developments, whether commercial, industrial, or subdivision. Vacant developed sites that have not been utilized for more than six months and other developments, the size of which are more than ¼ acre, are likewise mandated to conform to this requirement.
However, not all structures and developments must observe the LID requirements. Exempted from the said requirement are as follows:
- Existing single-family residential structures or lot prior which is not on a new subdivision
- Less than or 1-acre exact area residential subdivisions
- Less than ¼ acre developments
- Developments that plan to increase their impervious area or areas that would not absorb water to 5,000 square feet or lesser
The above-stated enumeration shall be exempted subject to compliance with other safety requirements and the absence of adverse effects to adjacent and other neighboring areas. Construction of Low Impact Development or LID can eliminate the need to build more expensive flood control structures and water detention and retention facilities.
Check with the city or county you plan to put up a commercial or subdivision development before finalizing any construction plans.
Passive Rainwater Harvesting
Passive rainwater harvesting is mandated for single-family residential or dwellings. You need to allow the water to soak into the natural ground by slowing down its flow and directing it to the soil. In the city’s publication “Residential Rainwater Harvesting: A Guide to Waterwise Planning and Design,” roof downspouts and driveways that slope to the street shall only be directed to landscape or natural areas. You must keep as much water in your lot or area as you can and not the water runoff get on the road. You can do this through various methods, including:
Swales are made by putting a mound at the end of the downslope to be a basin-like feature between the highest and lowest slope points. The distance of the swales from each other should be about 20 to 30 feet not to damage the terrain.
Another way is by building terraces, which allow water to soak in the soil and keeps the soil in place. These are a series of soil levels on top of one another that forms a stair-like form, and the face is usually covered with masonry, stone, or other materials that will hold the soil in place. Terraces are ideal for slopes steeper than three horizontal feet to 1 vertical foot, wherein swales are not practicable.
- Infiltration Basins
This is applicable for gently-sloping land or almost flat terrain. Infiltration basins can be manually built, but natural occurrences are also on the ground, like spots or vegetated depressions. They are highly suitable for planting and gardening.
Mulch can be made from various plant materials such as leaves, wood chips, nutshells, or non-living materials like gravel, rocks, rubber, and cinder. Another purpose of mulch, aside from holding water, is to slow down the process of evaporation. The ideal depth for mulch is 2 inches. Shallower than that and weed will grow, deeper would deprive it of air and precipitation. As for the material, shredded wood is highly recommended. It should not be hardwood or bark chips. The former doesn’t last long, while the latter floats in heavy rainfall. Rock is not an ideal material because it absorbs heat.
- Permeable Paving
This water-friendly surface can be an attractive driveway that still allows water to soak in the soil. It is porous or has cracked as part of the design wherein the water can seep through to reach the soil underneath the concrete or asphalt. Permeable paving is a way of having an attractive and tire-friendly driveway without compromising the soil over which it is built.
Active Rainwater Harvesting
Inactive rainwater harvesting, a catchment area, storage container, and distribution system is installed. This way, you can save and store the rainwater for a time and decide when or where you will use it.
All new developments ¼ or more acres in area are mandated to install active rainwater harvesting systems that would catch 1-inch rainwater or just enough water for the demand of annual landscaping. Exempted developments include:
- single-family residential
- developments that only have native or drought-tolerant plants in their landscape and observes passive rainwater harvesting
- there is an available non-potable water source in the area for landscaping
- food production areas like community gardens
There is also a required volume of stormwater to be reused for developments, which shall be equivalent to the impervious surface in square feet. Here are some ways on how one can engage in active rainwater harvesting:
- Storage Tanks and Cisterns
The easiest option under this category is by putting rain barrels just right under your downspouts or gutters. The most affordable barrel is that made of plastic and is 55-60 gallon in size. Say, for example, a 1,500-square-foot rooftop allows you to collect thousands of gallons of water with a typical summer thunderstorm.
In addition to the barrel container, you can opt to put it on a higher flat and durable elevation so that you will no longer need a pumping system to distribute the water. The gravity will do the work for you.
The more complex and much expensive option is to have cisterns installed in your home or structure. This would technically require some plumbing and pumping so that you would be able to have control and flexibility on how you will use the stored rainwater.
Inactive rainwater harvesting (RWH), the rule is if you want to catch a lot of rainwater, you have to prepare tanks sufficient in size. To solve how much rainwater you can expect to collect, you need to multiply your roof area in the square foot by the annual rainfall in your area by the conversion rate of 0.623 to gallons and the efficiency factor of approximately 90% for most types of roofs.
For example, (1,500 square foot) x (22 inches) x (0.623) x (90%) = 18,503 gallons of water per year.
Before installing a catchment system, you have to consider several factors such as the use of the water collected, expansion considerations, amount of rain that can be collected, overflow destination, underground or above-ground site of the containers, multi-use of containers for other purposes, flow system of the water from the catchment area to the container and its designated use, and whether the system will function with or without a pump.
Powder-coated steel is the best type of roof surface for rainwater collection because it is smooth and produces less debris. Since this will be the first thing that rainwater will land on, it is best to invest in the roof materials to ensure quality rainwater and less maintenance and upkeep of the other parts of the system.
The gutter must be positioned so that the flow will be outward and not toward the building. Hence, the inside face should be slightly higher than the outside face. The slope of the gutters must be positioned to ensure the downward flow of the water. The suggested slope is at a one-sixteenth inch per one foot, and hangers must be placed every three feet of the gutter.
The conveyance system that routes the water from the gutters to the storage container should be made of vinyl, PVC, galvanized steel, or seamless aluminum and should be fitted to the house’s side if possible. If not, one should make sure that it is properly sized, sturdy, and stable.
Screening and pre-treatment should also be observed to serve as filters for leaves and other debris before it goes to the container. It helps prevent the contamination of your water storage containers. It is usually made of wire mesh with holes a quarter inch in size and has a metal frame. The gutters, filters, and screens should be cleaned out regularly as well.
The storage tank or cistern should be opaque and screened to promote algae growth or serve as the breeding medium for mosquitoes.
The goal is to efficiently collect rainwater at the maximum level while ensuring that water loss is minimal throughout the entire process.
One of the cities in Arizona that offers incentives and rebate programs is the city of Chandler. It has been in place for almost three decades and has successfully reduced residents’ water use in the city. The city offers various types of rebates to which residents are eligible if they meet the following minimum requirements:
- Applicant must be the registered owner and utility consumer of the city of Chandler.
- Both front and back yards of the subject area must be entirely landscaped.
- The only included areas in the computation of 1,000 square feet’ minimum requirement are the landscaped area, patios, and decking.
- At least 50% of the landscaped area must be planted with low-water-use plants of typical mature size from the Phoenix AMA Low Water Use Plant List.
- No fountains shall be constructed in the area other than those with recirculating water, cascading design, and non-spraying type.
The spirit of the program is for conversion. That is why those with existing low water use plants that have already met the requirements cannot be eligible if they redo their landscape.
- Turf Removal or conversion of grass lawns
Grass requires water to thrive and achieve the greenest color. Because of this fact, the city deemed it necessary to encourage residents to remove turfs and replace them with drought-tolerant plants or low-water-use plants to reduce the water needed for landscaping. This is where the landscape conversion rebate program plays a role. The city offers a rebate rate of $200 for every 1,000 square feet area of turf or grass removed and changed. The maximum amount you can claim is $3,000, and that is for 15,000 square feet area of removed grass. You can no longer claim any additional $200 exceeding after that. Strict compliance must be observed, and one must not circumvent the law by putting up plastic sheeting on the converted area as the material it is made of is non-pervious or does not allow water to seep through.
To qualify, one must set an appointment for a site inspection 30 days before starting the project.
- Xeriscape Landscape Installation
Xeriscapes are landscapes that require low water use. The rebate is $200 for initial and newly installed xeriscapes. Almost all city residents are eligible and qualify under this type of rebate subject to certain conditions. The whole front and back yards, which shall exceed 1,000 square feet, must all be landscaped. The total grass area of the entire landscape must not exceed fifty percent (50%) thereof. The other 50% shall be composed of drought-resistant trees, flowering perennials, succulents, lush shrubs, and other Arizona Desert compatible landscape plants.
- Weather Based Smart Irrigation Controller
A cap of $250 rebate per unit will be given to residents who will install weather-based irrigation controllers in their landscapes. This new technology will determine and apply the right amount of water depending on several factors like the weather, soil type, moisture, rain, plants found on the landscape, and many others.
The rebate is limited to one unit for residential applicants and five units for commercial, industrial, or multi-family applicants.
However, the rebate funds are not unlimited, and applications for rebates are processed on a first-come, first-served basis until said funds are depleted.
Other cities and counties do their part in conserving water and making more green spaces through rainwater harvesting and other little steps toward the same goal. In Lancaster in Yavapai County, they have made cuts in their sidewalk curbs to direct and allow rainwater to soak in the soil beds and reenergize the plants.
Rainwater harvesting helps the community as a whole as each sector, such as the individual resident, commercial developments, the local government, and nature, benefits from collecting, storing, and using the collected rainwater. Here are some of the benefits of rainwater harvesting:
1. Helps in the conservation of limited water.
2. Reduce the use of potable water.
3. Free water means savings on the water bill.
4. Reduces the possibility of off-site flooding.
5. Less discharge of polluted water runoff and other pollutants into the streets and bodies of water.
6. It supports plant life by quantity, quality, salt-free irrigation.
7. Less possibility of soil erosion by holding water on site.
8. Groundwater recharge is maximized.
9. Your water bills will decrease.
10.Increases water supply.
The rainwater collected can then be used for non-potable purposes such as cleaning, toilet flushing, watering, irrigation, fountain filling, ornamental pond, or simply as a stock water supply. If you want to use the water collected inside the house, the water must undergo treatment, filtration, and disinfection to be safe for such and limited purposes.
Aside from the benefit and savings rainwater harvesting can provide to homeowners and business owners alike, the practice can also help in stormwater management and can reduce flooding in the area. It is also a water conservation method and can be a steady supply of water if done right.
It’s like having water for free without having to pay for utility or service. The rainwater that falls on your property becomes your property, and you can use them in any way and purpose you want within the limits set forth by the State of Arizona.