Water Security: How to filter rainwater at home

Water Security: How to filter rainwater at home

Table of Contents
Table of Contents

Water is essential for our bodies; it lubricates our joints, helps us think clearly, and removes waste from our bodies. This is why you should aim to always have a secure supply of water at home. Whether you are a homesteader, prepper, or simply curious about how to filter rainwater at home, this article will teach you about water treatment.

As rainwater falls from the sky, it collects debris, chemicals, and other pollutants, making it unsafe to drink. You will need a rainwater harvesting system and filtration system to ensure the water is safe. After filtration, filtered rainwater will be safe to use for up to 6 months when stored properly in a fridge.

Let’s begin by explaining why you should harvest rainwater.

Why you should Harvest Rainwater for Drinking

Although rainwater is bountiful, clean water is not. In an emergency scenario, we may not have access to clean drinking water and would need to harvest and filter rainwater for drinking. Filtered rainwater can also be used to water survival crops in your garden, for showering, and for cooking.

To become truly self-sufficient on a homestead, you will need to have a solid system for harvesting rainwater. Water is a valuable commodity as it is essential to sustain life, and as many parts of the world are experiencing droughts, it will become even more valuable. Having excess clean drinking water means you can trade for other useful resources as well.

Rain barrel in tropics

An easy way to Harvest Rainwater

Before you can filter rainwater for drinking, you will need to collect it. You can find our detailed article on capturing rainwater on our blog, but we will cover a step-by-step process below.

  1. Catchment Area: The best tool to capture rainwater is your roof. Roofs automate your catchment system since the rainwater lands on a wide surface area with a downslope angle and falls into a conveyance system. When it rains, you will know that water is flowing into your storage area. However, do keep in mind that corrugated metal roofing is the only roofing suitable for rainwater harvesting. Other types of roofing have chemicals that can leach into the water, making it impossible to filter properly.
  2. Conveyance: Once the rainwater lands in the catchment area, it needs to be transported. A downspout drainage or a gutter that flows water into a rain barrel would work best. For transporting water, it’s best to use a seamless metal gutter that flows into a downspout and pours water into a container. Galvanized stainless steel, copper, or aluminum is the best material for the conveyance system as it has long durability. You should also aim to clean your conveyance system every 3 to 6 months so that debris and pathogens do not build up.
  3. Pre-Filtration: To eliminate much of the debris that falls into the gutter, you can use a mesh screen. This reduces big pieces of sediments from entering your gutter, making sure the rainwater has fewer contaminants and is cleaner. You should also consider a diverter for your downspout. This will separate the water from debris, allowing cleaner water to flow into the storage location.
  4. Storage: You will need a dedicated storage location for your collected rainwater. This could be an above-ground or below-ground solution, but harvested rainwater is normally kept in a water tank, rain barrel, or water butt. They are durable in most climates and are made from material safe for water storage.
  5. Water Pump: With a water pump, you will be able to transport the water from the storage system throughout your house. The flow of water and increased pressure from the pump gives your more applications for using water. Some examples include gardening, cleaning, and bathing with the rainwater you have collected.
  6. Post-Filtration: Once you have developed a rainwater harvesting system for your home, you can begin the post-filtration process to turn your rainwater into drinking water. Some popular methods for post-filtration are using ultraviolet (UV) lights, gravity filters, and quantum filtration, to name a few. We will cover it in more detail in the next section.

water filters

How to Filter Rainwater for Drinking at Home

Once you have collected rainwater, it’s time to start filtering the water. Up to this point, the water may look clean, but it still requires additional filtering and purification to make it safe to drink. Most filters will filter 1mm, but a good filter will go down to 0.5mm. Fortunately, there are many different solid filtration systems that can be installed and kept in your home.

Quantum Filtration

A quantum filtration system is probably one of the most effective methods for filtering water. It works by using the principles of quantum mechanics for electron movement to create charged surfaces that neutralize 99.99% of harmful bacteria and viruses. Plus, it requires no electricity and little maintenance to operate, putting less of a strain on your at-home electrical system and decreasing your utility bill too. These filters are ideal for off-grid homesteaders as it is an automatic filtration system that requires no electricity and limited upkeep.

The main downside of this filter is the cost. You would have to replace the filter every two years and the UV lightbulb yearly. However, the cost may be offset by the money you save from electricity.

Ultraviolet (UV) Light

A UV light filtration system treats prefiltered water by killing pathogens. When pathogens and other living organisms in the water are exposed to ultraviolet wavelengths, it disrupts their DNA, making them unable to replicate and causing you to get sick. This is an effective and secure way of eliminating pathogens in the water.

The main downside of a UV light filtration system is that it requires lots of power to operate. This may put a strain on your electrical capacity if you are relying on renewable energy like solar. And if the power goes out, you may be stuck without safe water. Additionally, this system does not filter out small debris. Ideally, the pre-filtration phase of your rainwater harvesting method would have captured any debris, and the UV light can be used to remove any harmful pathogens. Another downside is that you will also have to replace the UV lightbulb once a year, and the price can be high depending on the bulb you order.

Gravity Water Filter

These filters use the force of gravityberkey water filter to push water through filters, cleaning the water of pollutants and sediments in the process. These filters are usually made from stainless steel, food-grade plastic, or ceramic. It works by pouring water into the top of the container, and then you let gravity do its job. The water will slowly distill through a filter. There are many different types of gravity filters, but the most popular brand is Berkey Water Filters. It eliminates 99.99% of pathogens and sediments in the water. We highly recommend these, because we used them ourselves.

The main downside of this filter is you have to pour water manually, likely daily, so it may take up some time. You also have to check on it regularly to make sure you are not running low on clean water.

DIY Rainwater Filtration System

When in an emergency and you need to make an impromptu water filter, you can make a Do-it-Yourself (DIY) rainwater filter. This process may be more challenging and labor intensive, but know it can give you some relief given that you can filter rainwater for drinking using easy-to-find material near your property. With some basic tools such as gravel, mosquito nets, sand, drill, large food-grade barrels, and a water pump, you can have an at-home filtration system. Below is a helpful video on how you can make a filter at home.

Solar Pasteurization

Solar pasteurization is water disinfection through heat without boiling water. At a constant temperature of 149-167 °F (65-75°C) for 1 to 4 hours (depending on the time to heat to these temperatures), water achieves the same effect of a rolling boil for 1 minute.

This method works by using a blackened container in a solar cooker. As the cooker uses reflective panels to direct sunlight into the cooker, it heats up the water exposing it to high temperatures. You should be repositioning the container regularly so the whole container is exposed to heat.

Using Solar pasteurization to kill pathogens is an energy-efficient way to filter water; however, it will not be enough to remove sediments from the water. Ideally, as you harvest rainwater, it will go through a pre-filtration system to ensure water quality.

Disinfect Water with Iodine

In an emergency, you can rely on iodine to disinfect water. You can add five drops, or two tablets, of 2% tincture of iodine for each liter of water. If the water is cloudy, double the dosage. The iodine is used to neutralize harmful pathogens in the water. After placing the iodine in the water, stir the bottle and wait 30 minutes for it to dissolve. The downside of this system is that it does not remove the chemicals in the water, nor does it remove any heavy metals, and it tastes like iodine. However, the water is safe to drink in an emergency. Before getting to the point where you have to rely on iodine, we suggest seeing if you have a heat source to boil water.

Boiling Water

Through boiling water, you will neutralize harmful pathogens in the water. This is a simple method to do at home; it will simply require water, a pot, and a heat source to get the water to boil. Once the water starts to boil at 212°F (1oo°C), keep the heat on for at least 1 minute or 3 minutes if you are 5,000 feet (1,000 meters) above sea level. Once the water cools, place it in a clean container and cover it. To improve the taste of boiled water, you can add a pinch of salt to each liter of water and stir the container.

Carbon Filter

carbon filter removes metals, chlorine, chemicals, and other dangerous compounds from unfiltered water, making it a much healthier option than regular tap water. Carbon filters do this by a process called adsorption, in which contaminants gravitate to the surface of the activated carbon. As water moves through the filter, contaminants are removed from the water. There are several variations of carbon filters, but generally speaking, they are affordable and can last for 18-24 months of continuous usage.

water storage location drain-spout

How to Prevent Rainwater from Stagnating

Stagnant rainwater has a foul odor and is a breeding ground for dangerous pathogens. So, you should do your best to prevent rainwater from stagnating. Fortunately, there are simple actions you can take to prevent it from happening.

  1. If your water is above ground and exposed to the air, try to go through your water supply in 10 days. Anything more would give mosquitos time to breed in the water.
  2. Store rainwater in a dark, food-grade barrel. By keeping sunlight away from the storage location, it prevents algae and bacteria from growing.
  3. Use a lid to cover the barrel. By doing so, you prevent leaves, branches, and other contaminants from entering the water after it is transported through a gutter or downspout.
  4. Make sure to check your gutters every 3-6 months to ensure they’re clean and contaminants do not get past your pre-filtration system.
  5. If the rainwater is not used for drinking, consider using non-toxic mosquito dunks to kill any mosquito larvae in a rain barrel. The rainwater will still be safe to use on your garden or animals.
  6. When you empty out your barrel, scrub the barrel with vinegar. This removes most of the contaminants in the barrel but is not harmful to plants or animals.

safe drinking water

How to make Rainwater Safe for Drinking

When turning rainwater into drinking water, there are two things to keep in mind as you make the water safe for consumption. You want to remove sediments and pathogens. In the time the rainwater falls from the clouds to your filtration system, it has collected harmful chemicals, dust particles, pebbles, branches, and other contaminants into the water.

Once the water is in a storage location, you aim to reduce light and heat exposure as it can cause algae growth, mosquitos to populate, and other organisms to grow. You should be especially cautious if you have an above-ground storage tank, as rainwater should be kept in an opaque container that shields the water from direct sunlight.

People also Ask

Some of the more frequently asked questions we have come across are:

The best roof for collecting rainwater is galvanized steel or stainless steel roofing. But you should also consider aluminum, copper, clay tiles, or cement tiles. These are ideal because alternative roofing materials have harmful chemicals that can leach into the water and are difficult to remove in the filtering process. Before buying roofing material for your property, you should speak with a roofing company to see if it is compatible with your house.

For every 1,000 square feet of catchment area, you should be able to get about 550 gallons for every inch of rainwater. So to figure out your need, simply divide your surface area by 1,000, multiply it by 550, then multiply it again by the annual inches of rainfall in your region.

The average American consumes about 25-40 gallons of water per day. So a person would need about 750-1,200 gallons of water per month or 9,000-14,400 per year. A family of four should be prepared to use 37,000-61,000 gallons of water per year.

Generally speaking, a 15°-30° slope would be ideal for rainwater to pour into your gutter and travel to your water storage location.

Besides the fact rainwater comes from clouds and groundwater from the ground, they differ in pollutants, alkaline levels, and accumulated debris. As rainwater falls onto the catchment area, it often captures dust particles, twigs, leaves, and other contaminants. Additionally, it is generally considered “soft water” because of its low mineral content. Groundwater, on the other hand, is considered “hard water” and would need to be filtered and purified before it can be used for everyday use.

To put it simply, potable water is safe to drink, and non-potable water is not safe to drink. Potable water can and should always be used for cooking purposes. Non-potable water is best for cleaning purposes.

No, non-potable water should never be boiled and used to wash or cook food. It has been contaminated and may contain chemicals that are not easily neutralized due to high heat. It’s better to be safe and avoid consuming non-potable water.

If you are keeping rainwater for usage outside, the water should be used and replaced every ten days. This will prevent mosquitos from breeding in the rain barrel. However, you can extend the shelf life of rainwater by using mosquito dunks for mosquito larvae and chlorine to kill algae as well as pathogens in the water. This water is not safe to drink but can be used in your garden.

For the best flavor and quality, filtered water should be consumed within a few days of filtration. However, filtered water can be stored for up to 6 months in a fridge after filtration.

Yes and no. Rainwater is evaporated water, naturally distilled from the sun. So it is clear of all pollutants. However, rainwater gets contaminated as it falls from the clouds. As it falls, it’s exposed to pollutants in the air, chemicals, and debris, making it unsafe to drink naturally. Fortunately, it can go through a filtering and purification process, so you can drink it afterward.

Shelf Life of Rainwater

Wrapping Up

To close up here, there are many ways for rainwater to be filtered and made safe for drinking. For the best water quality, you should consider multiple layers of filtration to remove sediments and pathogens. Fortunately, you can model your home to automate your water filtration system. From collecting rainwater down to making it safe to drink.

After the water lands in the catchment area, it will flow through the conveyance system, being filtered before landing at the storage location. From here, the water can then be filtered and purified for safe drinking.

Is your Water Safe?
Untreated water may contain harmful contaminants
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