How Much Does a Rainwater Collection System Cost to Install?

Average Rainwater Harvesting System Cost

Rainwater Collection System Costs by Method

Rooftop rainwater harvesting and surface runoff harvesting are the two primary methods of collecting rainwater. While the purpose, collecting and storing of rainwater remains the same, the methods vary considerably.

Rooftop

Rooftop rainwater harvesting costs an average of $3,000, or between $1,000 and $5,000. This method is the more affordable of the two and is the easiest to set up. The roof becomes the catchment device, directing the rainwater into guttering, where it flows into a storage tank for later use.

Surface Runoff

At an average of $11,500, surface runoff harvesting is significantly more expensive than a roof catchment system. You can pay anywhere from $8,000 to $15,000 for this setup. It's more expensive because of the sheer amount of time and labor required to excavate the area for the tank and the installation of the tank. 

Surface runoff systems have grates installed beneath the ground, where excess rainwater can pass through into pipes, directing it to the storage tank. This helps to control erosion from surface runoff and is an economical way of watering garden plants or topping up a pond in dry weather. However, it's very costly and, because of the risk of cross-contamination, the system must be a minimum of 10 feet from a closed sewer line and 50 feet from an unsealed sewer line.

Rainwater System Cost Breakdown

Regardless of the type of system you choose, they require the same basic components, a conveyance system, a collection method, a filtration system, and storage. Without any one of these components, a rainwater system will not function.

Filtration System

A rainwater filtration system typically costs between $1,200 and $3,100 for just the system itself. Find a plumber in your area to see rates for this project.

Conveyance System

A conveyance system for your rainwater collection can cost between $100 and $1,500, depending on how complex a system you need. How many pipes and fittings you need largely determines the system’s cost. 

Water Storage 

A simple rain barrel will cost around $120, while a multi-tank underground system could cost as much as $6,000. The price of water storage containers varies based primarily on the amount of water you’ll store and the exact type of storage you’ll need.

Collection Area

Average costs for the collection area vary by system type and size and range from $500 to $9,000. The collection area for a rooftop collection system consists of the gutters and the roof. The collection area for a surface runoff system includes whatever section of ground you designate as where you want the water to flow towards and into your tank.

Rain Barrel Cost

Installing a 100-gallon rain barrel could cost anywhere from $120 to $1,600, depending on the material and labor. Plastic barrels are the most cost-effective but might not last as long. If you’re planning on connecting your rain barrel to an irrigation system, you’ll pay more for labor.

Rain Barrel Installation Cost

Hiring a handyperson costs from $70 to $250 for rain barrel installation, not including the barrel. Barrel installation could be as simple as finding the best spot to set it up, or it could involve more complex gutter work. Some people even set up sprinkler systems with their rain barrel, which will cost more to install.

If you need additional exterior work to get the rain barrel in place or want to add on extra features, your project prices will increase:

• Gutter installation costs: $1,030 on average

• The cost to repair gutters: $180-$530

• Sprinkler system installation prices: $1,740

Rain Barrel Prices

Rain barrel prices vary by material and size, but usually run between $0.50 and $4.00 per gallon. Most homeowners pay around $140 for a smaller, 40- to 60-gallon barrel.

Cistern Cost

The price to install a cistern spans from $150 to $21,000. Prices on the low end reflect above-ground cisterns that are 50 gallons or less.

The reason prices vary so much is because, unlike a rain barrel, a cistern can go above or below ground. Installing a 150- to 200-gallon cistern above ground might not cost more than $660. An underground, 5,500-gallon concrete cistern with UV sterilization is $21,000.

Above-ground cistern prices are usually the same as rain barrel prices, between $0.50 and $4.00 per gallon. Galvanized steel tends to be the most expensive material. An above-ground, 1,000-gallon steel cistern costs $2,010.

Underground cisterns are significantly higher in material costs.

Cistern Installation Cost

Just the installation for a cistern could run upwards of $12,000 or more. An above-ground cistern might only cost between $70 and $250, similar to the cost of a rain barrel, but underground cisterns will dramatically raise installation costs.

With an underground cistern, you might see some of the following project components and prices:

• Excavating costs: $50–$200 per cubic yard

• Water filtration system costs: $1,000–$4,200 or more for a whole-house system

• Cost to regrade a lawn: $15 per cubic yard

• Plumber rates: $45–$200 per hour

• Piping costs and pumps: $200–$500 for a pump and additional costs for piping and job complexity 

Water Cistern Systems Cost

Prices for a water cistern system might fall between $5,000 and $12,000. A full water cistern system usually includes routing water back to the house so that it’s safe for human use. Talk to a plumber near you for a quote.

Water Tank Prices by Material

Above-ground cistern prices are usually the same as rain barrel prices, between $0.50 and $4.00 per gallon. Galvanized steel tends to be the most expensive material. An above-ground, 1,000-gallon steel cistern costs $2,010.

Underground cisterns are significantly higher in material costs.

Concrete Tank Prices

The average price of a 5,000-gallon concrete tank is between $3,000 and $6,000.An underground, 5,500-gallon concrete cistern might cost between $17,000 and $21,000 to install, including excavation backfilling, grading, and water filtration. If you’re looking for a different size, know that the cost to pour concrete is about $4 per cubic foot, not including labor.

Steel Tank Prices

The average price of a 5,000-gallon steel tank is between $3,000 and $6,000. Steel water tanks range in cost depending on their size and storage capacity. If you just need a small tank, you can expect to spend around $300 for an 80-gallon steel tank. If you need a larger tank, those that are 3,750 gallons cost around $15,000.

Fiberglass Tank Prices

The average price of a 5,000-gallon fiberglass tank is between $2,000 and $5,000. Similar to water tanks made of other materials, fiberglass water tanks range in price based on storage capacity and size. Fiberglass water storage tanks range in price from $300 to $30,000. 

Polyethylene 

The average price of a 5,000-gallon polyethylene tank is between $2,000 and $4,000.Polyethylene water storage tanks are durable, easy to install, and low maintenance. The cost of polyethylene water storage tanks ranges from around $825 to $21,000, depending on the size and water storage capacity of the specific tank.

Rainwater Collection System Cost Factors

Alongside the basic system you choose, there are other factors, including wet versus dry systems, permits, guttering, and added extras that influence the cost to install a rainwater collection system. You also need to consider the ongoing cleaning and maintenance costs.

Dry vs. Wet System

A dry system refers to a rain barrel or roof collection system, where the water flows down the pipes and into the storage tanks. But the pipes remain empty between rainfall, hence the term "dry system." These are usually the most affordable systems, as they’re fairly simple setups that are easy to install, with above-ground storage tanks.

Wet systems usually refer to underground systems where the water travels into the pipes, but only goes to the storage tank as more water enters the pipes and forces the excess to spill over into the tank. Therefore, the pipes always remain full, hence the term "wet system." Wet systems cost more to install due to the more complex setup and because the installers have to excavate a sufficient space for the underground tank.

Downspouts and Gutters

Downspouts and gutters are a vital part of any rooftop water collection system. Downspouts typically cost between$300 and $600, while gutters cost $4 to $30 per linear foot, with an average total cost of $1,900 for a pro to install gutters. The cost of a gutter system is impacted primarily by the materials you choose and the lateral length of the accompanying gutter system.

Maintenance and Cleaning

Rainwater harvesting system maintenance typically costs $740 per year, plus any repairs. A simple rain barrel is the easiest (and most cost-effective) to maintain, as a simple cleaning a few times a year will do the job. Water filtration systems and underground cisterns cost the most in upkeep.

Here are some costs you can expect to encounter over the course of owning a rainwater harvesting system:

• For water filtration systems, expect to pay around $250 per year for new UV bulbs and filters.

• A one-time gutter cleaning costs $160 on average.

• Replacing a pump costs $1,800 and should happen every 20 years.

Add-Ons and Enhancements

While you can keep your rainwater harvesting system super simple—particularly if you only plan to use it in the garden—there are several add-ons you can have installed that help to improve your system. This is especially true if you want a more elaborate system.

Improvements to keep collected water cleaner and place less strain on your filter include:

• Installing inexpensive gutter guards 

• Adding a first flush diverter for cleanliness and safety

• Installing a pump to increase transport efficiency

• Adding a top-up system to prevent your water storage system running dry

Above-Ground vs. Below-Ground Storage

Above-ground storage is more affordable than below-ground storage, with above-ground systems starting at $1,000, installed. On the other end of the scale, below-ground systems can run you up to $15,000. 

Above-ground systems are fast and easy to install and work with most property types in most locations. The installation is non-invasive and can even work with your existing roof, gutters, and downspouts. 

For in-ground systems, the installation process is more complex and invasive. This system isn't necessarily suitable for all properties, as the tank has to be a minimum of 10 feet from a sealed sewer line and 50 feet from an unsealed one to protect the tank from contamination. 

Additionally, a pro must bury the tank, which carries a higher labor cost because of the excavation. It also limits the type of tanks you can use to the higher-priced ones, as the lower-priced materials often cannot withstand underground use.

DIY Rain Collection System vs. Hiring a Pro

If you’re looking to put in a smaller, easy-to-install rain barrel, there’s a good chance you can take this project on by yourself. However, you still might need to contact someone to work with your gutters to make sure they fit. It’s also important to do your research on how rain barrels work. You might not think it, but smaller barrels can flood from less than 1 inch of rain.

Larger rain collection systems and underground cisterns almost certainly require a professional. These projects can involve anything from land grading and excavation to setting up a water filtration system. Especially when redirecting rainwater for human use, it’s extremely important to rely on a professional for safety’s sake.

Rainwater Laws

Depending on where you live, you may be required to obey certain laws related to rainwater collection. Rainwater collection is not illegal in any state, but some areas do face restrictions. If a state enforces restrictions, it is usually because that area experiences drought or other issues with water access. 

Thirteen states allow rainwater collection with some restrictions, 17 states allow it without restrictions, and 20 encourage or incentivize it. To find out if your state has rainwater laws, reach out to your local government and ask directly.

FAQs

How do you install a cistern system?

Installing a cistern can be as easy as placing a barrel or tank underneath a downspout or as complex as putting one underground. For underground cisterns, a team will excavate land, place the cistern and route it for irrigation and/or household purposes, then fill the land back in once set up. If using the water throughout the home, a professional will also hook it up to your home’s plumbing

How does a cistern work?

A cistern collects rainwater from either gutters and downspouts or rainwater seeping into the ground. You can repurpose that water in a number of ways, such as for a sprinkler system, for watering your garden, or even for filtering into potable water.

How long can you store rainwater?

The length of time that you can store rainwater depends on the condition and purpose of the water, as well as the collection system. For watering your garden or lawn, water is fine to use for a long time as long as algae don’t start to grow. For water drinking purposes, water can last indefinitely as long as it’s properly treated and in a container that doesn’t break down.

How much rainwater can I collect?

For every inch of rain that falls over 1,000 square feet of collection surface, you can collect between 550 and 630 gallons of rainwater. In other words, if you have a 1,000-square-foot roof and you get half an inch of rain directed to your harvesting system, you’ll collect 225 gallons of water.

Is harvesting water cost-effective?

Most people consider rainwater harvesting to be very cost-effective. While initial costs come with setting up your rainwater collection system, it allows you to access free water on an ongoing basis. 

You can use collected rainwater for things like landscaping or regular lawn watering, but with the right equipment, you can use it for things like cooking, bathing, and drinking. If you live in an area that encourages rainwater collection, you might also be able to claim tax incentives both when you install your system and each year that you use it.