Rainwater Collection Tanks – Best Tanks for Harvesting Rainwater 2023

Last Updated on April 14, 2023 by Mattias

In this article, we will go through rainwater collection tanks.

Below you’ll find everything you need to know about rainwater tanks and how to use them for your rainwater collection system.

The storage of rainwater is becoming increasingly popular; some do it for the environmental benefits, while others want to become independent of their water consumption or have the water for fire protection due to all the forest fires we’ve seen in the last few years.

But if you live in an area with little rain, you might want to look over plastic rain barrels instead. Or check out our guide on Rainwater Barrel DIY.

Let’s dive in!

What Rainwater Storage Tank Should You Buy?

There are multiple storage tanks to choose from, and you must get the right one.

Because if you want to harvest every inch of rain that pours down and become self-sufficient on water, you might need a large storage tank.

But before you buy a tank to store rainwater, do our step-by-step checklist for purchasing a rainwater collection tank:

Checklist For Buying a Rainwater Storage Tank

First, you should look at the rainwater harvesting yield:

  • Is it possible to harvest rainwater in a tank where you live?
  • What does the annual rainfall look like?
  • What’s the average rainfall
  • Capture the area, like the size of your roof. Every square foot can increase the amount of water, so ensure the exact numbers. Use this calculator to see how much rainwater water you can harvest.

What should you use the water for?

Each American uses, on average 82 gallons of water daily in their home.

Water usage in your home:

  • Dishwasher
  • Shower
  • Washing machine
  • Toilet flushes
  • Bathtubs
  • Hygiene (washing face/hands, toothbrushing)
  • Drinking
  • Cooking
  • Livestock watering (if you live on a farm)

Local restrictions

In some places, there are restrictions, while other areas are encouraging people to start their rain collection.

New Jersey, South Dakota, and West Virginia are some encouraging states.

Rhode Island, South Carolina, and North Dakota are blank “legal” states.

North Carolina got restrictions. You can read more about it in our article about if harvesting rainwater is illegal, where we go through all states and their view on rainwater collection.

Most people forget how much water we use, and it’s easy to take the water for granted…but having more water sources or a complete system that supplies your home with water is something you truly should consider.

If there are natural disasters, for example, it can turn life upside down and even affect your local water supply in some cases.

Water is and will always be our number 1 source of life.

Buying Guide For Rainwater Collection Tanks

You should now understand tanks and how important they can be for yourself and your family. Having your water supplies can give you peace of mind if something happens.

But how big a tank should you buy? Since the average family in the United States uses 300 gallons of water daily, we can do a quick count:

300 x 30 days = 9000 gallons a month.

Does this mean that you need a 9000-gallon plastic tank? Well, both yes and no.

It all comes down to what you should use the water for. Some might be happy with just a 9000-gallon backup. At the same time, others want to be able to be without water for months.

If that’s the case…you need a much bigger tank.

Before showing you the tanks, you must understand how important it is to buy high-quality. We can’t stress this enough.

A tank MUST: Compile with U.S. Food and Drug Administration regulation 21CFR 177.1520 (1) 3.1 & 3.2 for potable water storage.

Best Economic Tank

10 000-gallon tank from Enduraplas. Plastic tanks are the most common tank due to the price and quality of most tanks give.

10000 Gallon Plastic Water Storage Tank
High Durability
Limited storage use
Economical Solution for storing rainwaterCan get UV sun degradation of the plastic
Sidewall StrengthSensitive to wildfires
Heavy-Duty Roof ConstructionNo level gauge (but this can easily be solved with a Tank Monitor)
Algae Resistant (complete darkness inside the tank)
Food Grade Approved (safe to drink from)
FDA-approved polyethylene plastic resin
3 Year Warranty
It comes in a variety of colors

Is this for you?

If you’re serious about storing rainwater, this tank is perfect to start with, but as we mentioned, it all comes down to your uses.

A vertical tank can be used for:

  • Rainwater collection.
  • Well, water storage.
  • Fire suppression.
  • Bulk water delivery storage.

Best Tank for the “Big” family

20 000-gallon tank from Norwesco

Norwesco Industries is a leading manufacturer in North America of proprietary rotationally molded polyethylene tanks for above-ground tanks & liquid storage applications.

Here’s a big ONE.

A 20 000-gallon rainwater harvesting tank, perfect for the big family. Norwesco has over 82 years of experience in the tank business, and if you’re looking for a high-quality tank? This is it.

FDA-ApprovedIt only comes in one color (white)
High QualityExpensive (but a good investment for sure)
Big Storage
UV Inhibitors
NSF 61 Approved Resin
Long Lifespan

A vertical tank can be used for:

  • Rainwater collection.
  • Well, water storage.
  • Fire suppression.
  • Bulk water delivery storage.

Steel Tanks

Steel tanks are perfect, and who doesn’t love the look of stainless steel? Their capacity goes up to 1,000,000 gallons!

It’s a very durable and long-term water storage solution. Texas Metal Tanks offers many fine tanks. But if you want a tank with high capacity, check out the Steel Tanks that Tank-Depo offers their customers.

Fiberglass Tanks

A fiberglass tank is also a good tank for rainwater harvesting and can be found in various colors, and is very easy to paint or set murals around.

Large Tank vs. Multiple Smaller Tanks For Rain Harvesting?

Two smaller tanks can increase the amount of rainwater you can harvest; it can also be more cost-effective than buying one large tank. Both tanks can get you gallons of rainwater, but if you’re on a budget, compare. (example 1000 gallon tank vs. two 500-gallon tanks)

Are Rainwater Tanks Worth Buying?

Yes, they are worth it but try to see it as an investment rather than a cost from an economic sense of view. Rain tanks can decrease your water bills significantly, and the stored water can be used for daily household machines like the washing machine or the dishwasher.

But it can also be used for your vegetable garden or more significant tasks like landscape irrigation.

And if your water supply were cut off for some reason, a tank filled with water would genuinely be a piece of mind.

What Is The Best Type Of Rainwater Tank?

Fiberglass tanks are one of the best, but they are expensive due to the manufacturing process. Polyethylene (plastic) tanks are also perfect and probably the most popular option since they are durable and cheap.

Can You Drink Rainwater From a Tank?

If the proper steps are taken (harmful bacteria removed), drinking stored rainwater from your tank is safe. A tank properly maintained tank could provide clean water of high quality.

How Long Can You Store Rainwater In a Tank?

You can use the rainwater for drinking from 7 days to 30 years. The water never expires or goes bad but can become chemically or biologically contaminated. It can last indefinitely if you’ve been storing the water in a clean, dark, cool, dry area and away from harmful chemicals.

However, it’s good to rotate the water from time to time.

What Is The Purpose Of a Rainwater Tank?

The purpose of rainwater tanks is to collect stormwater runoff from surfaces like roofs and reduce the water that enters our waterways. The water can then be used for different purposes. One good idea would be to use it as potable water storage to ensure you got water if something happens.

What Happens When The Rainwater Tank Is Empty?

Then the system will switch to the drinking water supply network. Buying any tank gauge can be a brilliant idea. With a wireless tank gauge, you can even track your rainwater levels inside your home with the help of an app.

How Often Should Rainwater Tanks Be Cleaned?

It’s best if a rainwater tank can be cleaned every 3 to 6 months. The standard recommendation is to do it yearly. But 3 to 6 months is ideal.

It’s also good to clean it after heavy rainfall to ensure the chamber is empty and clear from blockages. Some systems have a flush device, but this isn’t always the case.

Do Rainwater Tanks Save Money?

Yes, you can save money, and if your tank is installed correctly, you can save up to 40% of your water bill.

Do I Need a Filter On My Rainwater Tank?

Maintaining rainwater’s chemical, microbial, or physical quality should not be necessary. But it must be purified before it’s used in your home to remove sediment, bugs, bacteria, or debris. 

What Is a Wet System In a Rainwater Tank?

A wet system (also called a “charged system”) is when the pipes from your gutters run underground to your water tank. Since the pipes are underground, they can be full of water even during dry periods without rainfall.

Can Rainwater Be Stored Underground?

Yes, by using an underground rainwater tank. Which is ideal for storing rainwater and very good since it protects the tank from light and heat.

Rainwater Collection Tanks Summary

I hope you liked this article about rainwater collection tanks.

As you discovered, there are many reasons to store rainwater, but in the future, it will probably be more popular and essential for every household to have a water source ready.