How to Filter Harvested Rainwater

Best water filtration for harvested rainwater

Why Harvest Rainwater?

Rainwater harvesting is becoming increasingly popular as a sustainable source of water for homes, businesses, and farms. However, harvested rainwater may contain contaminants that can be harmful to human health. One effective way to treat collected rain water is by using ultraviolet (UV) water purifiers.

Uses for Rainwater

Cup of water
Potable uses such as drinking, bathing & cooking
Non-potable uses, including washing clothes & flushing toilets

Watering & irrigation

Can You Drink Rainwater?

While rainwater is generally safe to drink, it is important to remember that it may contain harmful contaminants such as bacteria, viruses, and chemicals. The safety of rainwater for drinking depends on several factors, including the source of the rainwater, the collection system, and storage method.

Be aware that carbon dioxide in the atmosphere can reduce the pH of rainwater, making the water aggressive on household fixtures or piping. Bacteria can also grow in the rainwater catchment barrels.

For these reasons, we recommend always filtering harvested rainwater before drinking.

Did You Know?

Rain harvesting barrels my collect more than water. Rainwater runoff might also catch:

        • animal droppings
        • leaves
        • insects
        • dirt particles

Bacterial Growth in Rainwater

Water sitting in storage barrels is often susceptible to bacterial growth and exposure to the elements, not to mention the attraction for mosquitoes and other insects.

For these reasons, it is best to treat the collected rainwater prior to consumption. This way, you can best guard against sickness.

UV water purifiers use UV-C light to kill bacteria, viruses, and other microorganisms that may be present in harvested rainwater. Unlike other water treatment methods, UV water purifiers do not add chemicals to the water, alter its taste, or remove beneficial minerals. UV water purifiers are also relatively low maintenance, requiring only periodic replacement of the UV lamp.

Filter your rainwater with a UV light filter

Water Filtration Solutions for Harvested Rainwater

UV Light Disinfection for Collected Rainwater

Ultraviolet water purification system is an effective way to treat stored rainwater to guard against 99.99% of waterborne bacteria, viruses, and pathogenic disease-causing microorganisms such as Cryptosporidium and Giardia.

Rainwater is naturally soft so a water softener will not be needed. But a sediment prefilter or a pre-assembled integrated filtration system is a good idea.

Sediment Prefilters

Turbidity is the quantity of suspended solids in water which often causes cloudiness and should be a consideration when treating harvested rainwater. Water collected from roofs and gutters may contain leaves, roofing debris, and dirt particles. These suspended solids require a prefilter be installed with the ultraviolet purification system, as UV will not work effectively if turbidity has not been properly addressed.

One simple solution would be to install an "integrated system" such as the Viqua IHS22-D4 that combines powerful UV treatment with prefilters to remove debris and improve the taste, odor and appearance of the water.

The Viqua IHS22-D4 is compact and conveniently designed to include three stages of filtration to make sure all harmful microbes, such as cryptosporidium, giardia, E. coli, legionella, norovirus, and hepatitis A virus †, have been inactivated in your collected water. The integrated sediment filter removes fine particulates, while the carbon filter removes organics and contaminants from the water improving the taste and odor. The UV light then treats the water inactivating any living microorganisms. A simple plug-and-play solution for treating stored water.

Why Choose UV Disinfection for Rain Water?

Six reasons why ultraviolet (UV) disinfection is an effective treatment option for rainwater catchment:

    1. UV safeguards against waterborne bacteria and viruses
    2. UV requires little maintenance
    3. UV is environmentally friendly
    4. UV is a safe, natural process that requires no chemicals
    5. UV systems can come with 12-volt option for use with solar power supplies

Rainwater Filter Systems

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VIQUA IHS22-D4 UV Water Treatment System
  • The Viqua IHS22-D4 inclues two integrated prefilters to improve the taste and odor of your water.
  • LED Status system indicator.
  • All-in-one UV solution boasting added layers of water filtration and treatment.
  • Safeguards ALL the water coming into your home.
Viqua VIQUA IHS22-D4 Integrated 12 GPM UV System with Sediment and Carbon with Lead Reduction Filters IHS22-D4-

Viqua VH410-F20

The VH410-F20 is an ideal water filtration system for treating harvested rainwater. The powerful 18 gpm UV system is preassembled with a 5-micron sediment filter to significantly reduces dirt, rust, sediment,

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FAQs About Harvesting Rainwater

Why Harvest Rainwater?

Harvesting rainwater has many benefits. Here are some of the reasons why people harvest rainwater:

  1. Water conservation: Harvesting rainwater helps to conserve water by capturing and storing water that would otherwise be lost. This is particularly important in areas that experience frequent droughts or where water is scarce.

  2. Cost savings: Harvesting rainwater can help to save money on water bills by reducing the amount of water that needs to be purchased from a utility company.

  3. Environmental benefits: By reducing the demand for municipal water supplies, harvesting rainwater can help to reduce the strain on local water resources and the environment.

  4. Watering and Irrigation: Rainwater is free from many of the chemicals and minerals found in municipal water supplies, making it ideal for watering plants and irrigating farms.

  5. Emergency preparedness: Harvesting rainwater provides a backup supply of water in case of emergencies, such as natural disasters or power outages.

Overall, harvesting rainwater is a sustainable and environmentally-friendly practice that can help to conserve water, save money, and promote healthy plant growth.

Should Reverse Osmosis Filtration be Used for Treating Harvested Rainwater?

Generally, reverse osmosis filtration systems are not used to treat harvested rainwater.

If the intended use of the harvested rainwater is for irrigation or watering plants, the water usually doesn't need to be filtered.

If you plan to drink or cook with the collected water, you'll want to treat it with UV light (UV water sterilizer system) to ensure all microbial contamination, including viruses and bacteria, are removed. You might also filter the water with an RO system to ensure that the water tastes good, and is safe and free from a variety of contaminants.

Is rainwater safe to drink without filtration?

Rainwater can contain chemical contaminants, such as pollutants from the atmosphere or from collection surfaces. These contaminants may include heavy metals, pesticides, and other substances that can pose health risks if consumed.

It is generally recommended to filter rainwater before drinking, especially for long-term or regular consumption. Filtration methods like sediment filters, activated carbon filters, and UV disinfection can help remove or reduce contaminants, ensuring the water is safe for consumption.

What are the recommended filtration methods for rainwater?

Recommended filtration methods for rainwater vary depending on the specific quality of the collected rainwater and its intended use. Here are some commonly used filtration methods for harvested rainwater:

  1. Sediment Filtration: Sediment filters, typically made of materials like sand, gravel, or fabric, are used to remove larger particles, debris, and sediment from the rainwater. This initial filtration helps improve the water's clarity and prevents clogging of subsequent filters.

  2. Carbon Filtration: Carbon filters are effective in removing organic compounds, chlorine, pesticides, and certain chemicals from rainwater. These filters use activated carbon, which has a porous structure that adsorbs impurities as the water passes through.

  3. UV Disinfection: Ultraviolet (UV) disinfection systems use UV light to destroy or inactivate bacteria, viruses, and other microorganisms in the water. UV disinfection is often used as a final step after other filtration methods to ensure the water is microbiologically safe for consumption.

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