Frequently Asked Questions

About Rainwater Collection

What is rainwater collection?

Rainwater collection — or rainwater harvesting — is the gathering and storing of rainwater. Traditionally, rainwater harvesting has been practiced in arid and wet areas, and has provided drinking water, domestic water, water for livestock and water for landscape irrigation

How is rainwater harvested?

Rainwater is harvested two ways. Passive rainwater collection occurs when rain is collected in natural or mad-made earthworks such as ditches, ponds or swales. Active rainwater collection occurs when rain is collected in containers such as tanks, cisterns or rain barrels. Active collection lets the user control how much water is collected and access it when needed.

What are some typical uses for collected rainwater?

There are lots of ways to make use of captured rain. The best is landscape irrigation. Rainwater is the beverage of choice for plants and soil, and doesn’t contain harmful chemicals such as chlorine and salts found in public water supplies. Stored rainwater is a reliable water source that the user controls. Rainwater collection systems are usually linked into existing irrigation systems and provide a spigot to easily access rainwater with a hose or bucket. Systems may be integrated with gray-water recycling systems, too. Depending on the level of filtration and purification, stored rainwater can also be used for water features, fire protection, laundry, showers and tubs, cooking, and drinking.

I live in a dry region. Does it rain enough here for collection?

Yes! A typical 2,500 s.f. rooftop in Prescott, Arizona — a high desert area that receives just 13 in. of precipitation a year — can collect 21,600 gal. of fresh rainwater per year. That’s more than enough to water a typical landscape for a home this size, especially if plants have been selected for regional climate conditions. In areas prone to drought and dry-spells, rainwater collection puts a reliable water source in your hands without taxing precious water resources.

How much landscaping can I water with harvested rain?

That depends on how much you collect and what your plants require. Capture potential is calculated by multiplying collection area (total square footage of roofs and hard surfaces) by gallons of rainwater per square foot per year that your home receives. Visit our Resources page to download general information, calculation instructions and a spreadsheet to quickly determine your watering needs and collection potential.

Are rebates, tax credits or other financial incentives to collect rain available?

Several states and municipalities across the United States offer financial incentives for collecting rainwater. In Arizona, individuals may claim a tax credit up to $1,000 for installing a rainwater harvesting system. Additional rebates and incentives are available through local municipal water conservation departments.

How many tanks do I need? What size? How much do they cost?

Tank capacity is determined by many variables. How much can you collect? How will the rainwater be used and how much do you need? Does your region experience seasonal dry-spells and rainy periods that warrant a lot of storage? How much space do you have for above-ground tanks, or should you consider going underground? And how much do you want to spend? We’re happy to provide you a free estimate.

Do I need gutters on my house to collect rain?

Technically, you can collect rain from a rooftop without gutters by positioning containers under any spot prone to water run-off, but that’s not very efficient. Good rainwater harvesting system design carefully considers gutter size, screening and location to maximize collection.

Are pumps required to collect rainwater?

Pump requirements depend on several things, including how and where the water will be used, landscape topography and system design. Pumps are recommended for landscape irrigation.

Can I drink rainwater?

Do not drink untreated rainwater. While the quality of rain itself is usually good when it leaves the clouds, it passes through a lot of obstacles before reaching your spigot. Contaminants include air pollutants, roof dirt, chemicals around the collection area and decaying organic matter. Rainwater can be used for drinking when properly filtered and purified

Is rainwater collection legal?

Regulations governing rainwater collection vary by state, county and municipality. In Arizona, it is not only legal to collect rain, the state offers a tax credit incentive up to $1,000 for rainwater collection systems. Some cities require permits for rainwater systems, as do a few states. Most have no laws regulating rainwater collection. Check before installing a system.

I live in a community with a homeowners association. Will it allow rainwater collection?

More and more homeowners associations and similar bodies are embracing water- and energy-efficiency systems, including rainwater harvesting. Several states prohibit HOAs from restricting systems and some provide incentives to HOAs that adopt water conservation practices. In addition, manufacturers have responded by designing rainwater collection equipment such as Bushman low-profile and Slimline tanks that tuck neatly up against a wall in colors to blend in with house exteriors or foliage. Good design can also go far in creating a system that is compliant with HOA regulations. Check with your HOA before installing.

Where can I learn more about rainwater collection?

Start by visiting our Resources page. You’ll find essential information about how rainwater collection works, collection potential and water requirement calculations for your own home and more. Contact your local water provider, nurseries, university gardening programs or environmental organizations. Online resources also provide general information, news on incentives and legislation, books and guides, and more.

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