Best Roofs for Rainwater Collection

Best Roof For Rainwater Collection

Table of Contents
Table of Contents

If you’re a homesteader who wants to collect rainwater for drinking, you’re going to want to be extra cautious with how you collect your rainwater. Contaminated rainwater can cause you to get sick. So, you’ll want to keep your rainwater as clean as possible.

Rain’s first point of contact when it comes to your rainwater collection system is usually your roof. However, not all roofs are made equal, and some are better than others for rainwater harvesting. 

We previously discussed how to collect rainwater and how to filter rainwater for drinking, but today, we will let you know everything there is to learn about choosing the best roof for collecting rainwater.

Our short list for the best roofs for rainwater harvesting is:

  • Galvanized Metal
  • Corrugated Metal
  • Clay Tiles (Terracotta Tiles)
  • Concrete Tiles
  • Solar Panels

The roofing you decide to go with should depend on your budget, specific needs, and if it is suitable for your home and climate.

You should speak with a professional roofer before making a major decision, but read on below to learn more about the different types of roofs for rainwater collection.

rainwater harvesting

What Is Rainwater Harvesting?

Rainwater harvesting is the process of collecting run-off water in order to store it for later use. For most rainwater collection systems, a roof will serve as the primary catchment area.

After landing on the roof, the water will move into a conveyance system and be transported to a downspout. From the downspout, the rainwater will fill and settle in a water storage container. 

Since rainwater is soft water and high in nitrogen, it’s good to use for watering plants, washing clothes, cleaning, and there are many other uses for rainwater at home

rainwater collection

What Are the Benefits of Harvesting Rainwater?

Whether you are looking to become a self-sufficient homesteader or reduce your water bill, there are many benefits you can gain from harvesting rainwater. These include:

  • Free Water Source: Rainwater harvesting gives you a free source of water that you may use however you see fit. You’ll have complete control over the water supply, so it’s ideal for towns that have water restrictions.
  • Multiple Applications: You can use the rainwater you harvest in many different ways. Commonly, people use rainwater for irrigation systems, indoor use, and outdoor use. 
  • Emergency Resource: Even if you don’t use rainwater as your main source of water, you can use your collected rainwater as a backup supply in case of emergencies.
  • Easy to Apply: Most rainwater collection systems are easy to set up and use. What’s more, the equipment you’ll need to collect rainwater is inexpensive and won’t require much maintenance.
  • Environmentally Sustainable: Collecting rainwater is good for the environment because doing so helps conserve water. Additionally, using rainwater for your garden is good since the water isn’t treated with any chemicals.

raining on roof

Why Does the Roof Material Matter for Collecting Rainwater?

Roof material matters when it comes to collecting rainwater. A study found that roofing material can influence the quality and quantity of rainwater collected. Specifically, this study found that the material of the roof affects the pH, turbidity, total suspended solids, total dissolved solids, temperature, and metal content of water.

To explain this in simple terms, the roof will affect how safe the water is for consumption and how much water you can collect. Some roofs made from lead and cedar shake have dangerous chemicals when ingested through water. These can cause serious toxins to enter your body, which is the last thing you want to worry about in an emergency scenario.

What Are the Best Types of Roofs for Rainwater Collection?

Galvanized roof

1) Galvanized Metal

Although some people may use materials like asphalt, slate, or tile roofs to collect rainwater, most people prefer using metal roofs. They choose metal roofs not because they prefer metal but because contaminants don’t grow as much on metal roofs; metal roofs are often covered in anti-microbial paint.

Galvanized metal roofs have significantly lower concentrations of dissolved organic carbon and other bacteria compared to other roofing materials. This means that the rainwater you collect will have fewer disease-causing microorganisms.

Even if you do opt to use galvanized metal roofs, take care to filter and treat your rainwater before using it – especially for drinking. 

Corrugated Roof

2) Corrugated Metal

Corrugated metal roofs are made from metal sheets that are round and wavy and are placed over and attached to a roof with screws. There are many benefits of using these types of roofs as they are durable, relatively low cost, lightweight, long-lasting, and easy to clean. 

Like galvanized metal roofs, corrugated metal roofs have lower chances of microorganisms growing on them; however, there’s a chance that some zinc will be leached into your rainwater. 

Before drinking the rainwater, you collected on your corrugated metal roof; it would be wise to use a home test kit on a sample of rainwater to ensure zinc levels are within the allowable limits.

Clay Tiles Best Roof for Rainwater Harvesting

3) Clay Tiles (Terracotta Tiles) 

Clay tiles are made from natural materials and are baked into tiles. Although they are not as efficient as metal roofs for harvesting rainwater, there are a lot of benefits to using them. 

Some benefits of clay tiles include the following:

  • Made from natural products: Since clay tiles are made from natural materials, inorganic chemicals and toxins contaminating your rainwater storage are less of a concern.
  • Water Resistant: Clay tiles are resistant to fungi growth and water leaks because the material does not absorb water. 
  • Long-lasting material: Clay tiles are made from heavy and tough material and are known to last for over 75 years.
  • Heat-Insulator: Clay tiles also insulate heat, meaning more heat retains in your home during the cooler months of the year.

Despite the many benefits of clay tiles, they are expensive and difficult to transport because of their weight. 

Cement tiles best roof for rainwater collection

4) Concrete Tile

Concrete tiles are made with cement, limestone, sand, and water. Clay tiles and concrete tiles share many similarities, but they are also very different when it comes to collecting rainwater. 

Some of the benefits of using concrete are:

  • Durability: Since the tiles are heavy, they are resistant to storms, hail, and wind. Plus, they are more resistant to extreme weather changes than clay tiles.
  • Lifespan: Concrete tiles are known to last for over 50 years.
  • Heat Insulator: Concrete material is a good insulator of heat, making it a good roofing option if you live in a cold environment.

Using concrete tiles may raise the alkalinity in your water, but this isn’t necessarily an issue. You can ensure the pH of your water is within acceptable limits by using a home test kit. 

solar panel rainwater

5) Solar Panels

If you’re living off-grid, you may have considered solar panels to collect electricity. However, they can also be used as a catchment area for rainwater harvesting. Using them may seem counterintuitive, but they are made to be water-resistant. 

Solar panels are a good option for collecting rainwater because water rolls off the surface smoothly. However, if you’ve used adhesives when you installed your solar panels, it may be worth testing the water to see if there are any toxins.

What Roofing Materials Should You Avoid?

There are certain types of roofs that you shouldn’t use for rainwater collection. Certain roofs can contaminate water with chemicals and toxins that are difficult to filter out. We advise against using the roof materials below if your goal is rainwater harvesting:

Cedar Shake

Manufacturers usually treat wood shingles with fire retardants – something you don’t want in your collected rainwater. These types of roofs tend to retain sediments and containments, making them prone to mold and algae.

If you do have this kind of roof, you may still be able to use the rainwater for irrigation purposes. 

copper roof


Although copper is naturally resistant to algae and moss growth, copper can leak into rainwater. Water contaminated with copper should not be used for drinking or on plants. 


In some parts of the US, roofs are allowed to be coated in lead. Lead is a toxic chemical that should not be consumed by people. So you should test your roof for a lead coating before attempting to collect water.

Good Habits for Rainwater Harvesting

In addition to picking the right roof for rainwater collection, basic maintenance and good habits will reduce the number of sediments in your rainwater. Some steps you can take include:

  • Tree Trimming: By trimming the branches on your trees, you’re reducing the number of twigs and leaves that fall on your roof and gutter. Plus, it would allow for water to fall directly on your catchment area, meaning you can capture more water whenever it rains. Trees should be trimmed twice a year.
  • Clean Gutters: It is easy for gutters to collect sediments such as twigs, leaves, rocks, and dust over the months. Cleaning your gutters quarterly allows more water to flow into the downspout and reduces the number of sediments that go into your water.
  • Don’t use Coatings: Roof coatings such as biocide, algaecide, or fungicide can leach into harvested rainwater. This can be toxic and dangerous for consumption. 

People Also Ask

As long as you avoid roof materials that contain toxins and chemicals, it’s generally safe to collect rainwater on the roof. If you’re collecting rainwater for drinking, you’ll want to purify the water after collecting it. When it comes to collecting rainwater for watering your plants, it is not necessary to filter the rainwater beforehand. However, we suggest you do so since filtered rainwater is better for plant growth.

For every 1 inch of rainwater, you can capture 600 gallons of water for every 1,000 square feet in a catchment area. You can calculate how effective your rainwater catchment system is by using the following formula: Harvested Water (gallons) = Rainfall Depth (inches) x Catchment Area (sq. ft.) x 0.623.

The slope of your roof – the angle – will determine how fast water will leave your catchment area. A roof with a steep slope will shed water faster than a roof with a low slope. A higher slope is better for removing debris and foreign materials, as well as for preventing stagnant water buildup.

Final Thoughts

To recap, we’ve given you a rundown of why roof material matters when collecting rainwater and which roof materials are best. When picking roof material for water collection, you should aim to use a material that does not contain toxins and chemicals. For this reason, galvanized metal, corrugated metals, clay tiles, or solar panels would be best for harvesting rainwater.

When in doubt about the quality of your water, you can always take a sample of rainwater and test it for any contaminants.

Disclaimer: We are not professional roofers. Before making a roofing decision, make sure to speak with a professional to see if a type of roof is right for your home. We are simply preppers with interest in designing homes for off-grid living and homesteading.

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