How to Build a Rainwater Collection System

A lot of people used to have rain barrels in their yards, but did you know that you can build an entire rainwater collection system? No matter if you’re looking for a source of clean drinking water in a dry environment, a way to water your garden, plants, or flowers, or you want a way to top off your pond during the summer to keep the water levels correct, a rainwater collection system in the answer. This is especially helpful if you live in wet and humid environments where you get a decent amount of rainfall. If you live in colder environments where it routinely freezes, you’ll have to protect your rainwater collection system too. 

You’ll be able to catch the rainwater in it and distribute it later. You can make a complex or simple rainwater collection system, but both options are a great way to conserve water over the long term while lowering your water bill costs. If you’re someone who frequently waters their garden or lawn, or you live in a very dry environment that is prone to drought, having a rainwater collection system in place can help stave off the cost of relying on the municipal water supply. 

On average, your rainwater collection system will cost between $1,000 and $5,000 for the materials and the labor costs required to set it up. The total cost for your rainwater collection system will vary based on your location and how complex you want your system to be, but most people spend around $2,500 to install a 5,000-gallon dry tank rainwater collection system. If you plan on doing the installation yourself instead of hiring a professional, this can save your costs too. 

If you’re considering adding a rainwater collection system on your property and you want to know which factors influence your costs, this is for you. We’re going to break down all of the important components that come with this project and their price points, and you can get a rough estimate by adding up the ones that apply to your situation. Since this project can easily reach upwards of $15,000, setting a clearly defined budget in the start ensures you get the rainwater collection system you need without breaking the bank. 

1 Plastic Rain Barrel
If you don’t need a lot of water, you can get away with setting up a very simple rainwater collection system with a single rain barrel. More elaborate systems can easily hold thousands of gallons of water, but they will be more expensive to put in.
Rainwater Collection in Old North by Paul Sableman / CC BY 2.0

Price Points for Rainwater Collection System Components 

Each rainwater collection system comes with a host of components to consider, and some are optional. However, you’ll need a filter, conveyance system, collection area, and water storage on all of them. The prices will fluctuate depending on the type, size, and scale of your particular rainwater collection system. However, general estimates for these necessary and optional components include: 

Collection Area

The type of collection area you have will depend on the specific rainwater collection system you install. If you have a rooftop collection system, the collection area will encompass the gutters and roof. If you have a surface runoff system, the collection area is the section of ground where you want the water to go before it enters your tank for storage. The prices for these two areas have a huge fluctuation to them, and it depends on the property topography, system type, and your home’s size. A rough estimate is $500 to $10,000 for the collection area. 

Conveyance System 

Your rainwater collection system will need a conveyance system that consists of a host of fittings and pipes. The length of the pipes you need and the number will depend on the type of system and system size you install. Prices can start as low as $100 and go up to $2,000 or more if you choose a complex system. 

Downspout Screens

A downspout screen gets fitting at the top of each downspout on your system to serve as a thin filter that prevents leaves, bugs, or other debris from getting into the pipes and ending up in your rainwater collection system’s storage tank. They’re one essential piece for this system if you plan to use the water for home uses like bathing. You’ll pay between $10.00 and $30.00 a screen, and you’ll need one for every downspout. 

Filtration

Filtration may not be necessary in your specific rainwater collection system. However, if you plan to use the water around your house, you want to install a filtration system. This system will help get rid of any harmful bacteria or undesirable elements like remnants from weed killer or chemicals. Filters vary in functionality and style, but you’ll typically pay between $100 and $250. 

First Flush Diverter

If you want to use the rainwater from your setup in the home for drinking, bathing, or any other use, you’ll want to install a first flush diverter. This essential add-on will flush away the first layer of rainwater in your rainwater collection system since it’s usually filled with toxins and dirty enough to not be safe to use. This piece will cost you between $20.00 and $40.00. 

Gutter Mesh

You can install gutter mesh on your home’s gutter system. This mesh acts like a filter for bitter items like leaves or debris. You don’t want these items to get flowing right along with the rainwater and end up stuck inside your storage tank. Per linear foot of gutter mesh installed, you’ll pay between $6.00 and $10.00. So, longer systems will cost much more. 

Gutter Outlets

Gutter outlets are also more commonly called downspout connectors. You use these outlets to channel water from the gutter into your downspout. You should have a downspout spaced every 20 feet along your gutter, and every downspout will need an outlet. You’ll pay between $5.00 and $10.00 each, so more complex rainwater collection systems will need more. 

Pump

Having a pump in your rainwater collection system will make it much easier to distribute water through your pipes. It works to push the water along to make it easier to extract or push into certain areas of your home or yard like into your pond. In turn, it’ll be easier to reuse the water outside or inside. Your pump will cost between $150 and $300, depending on the size you need and the brand. 

Tank Gauge

A tank gauge is an optional part you can add to your rainwater collection system, but you may want to consider adding it if you want to keep a close eye on the whole system to ensure it’s running correctly. The gauge will let you see where your water level is at a glance inside the tank. A tan gauge will cost between $30.00 and $50.00 to buy. 

Tank Screen 

A tank screen gets fitted over the tank by your lid. It works to filter out leaves, debris, bugs, and other undesirable items you don’t want in your water. These screens work as another layer of filtration to help shield your rainwater from unwanted elements. On average, a tank screen for your rainwater collection system will cost between $10.00 to $30.00. 

Top-Up System 

If you add a top-up system onto your rainwater collection system, it does exactly what you think it does. It’ll automatically top up or fill your tank with water. This piece will stop the system from dropping below a set water level to prevent it from running dry in dry landscapes, and you’ll pay between $100 and $200. 

Water Storage

This is one of the most expensive parts of your rainwater collection system, depending on how complex it is. It can be something as simple as placing a simple rain barrel beside your home, or it can be as complex as a vast underground tan with a large capacity. Since there are many types of water storage vehicles, your costs can fluctuate between $100 and $4,000. 

2 Large Rainwater Collection System
The more pieces you add to your system, the easier it can be for you to operate and maintain. This can help you justify the higher cost once you get it set up, running, and collecting water for you to use.
Rainwater Collection, Gisenyi Hospital by Justin Kaplan / CC BY-NC 2.0

Type of Rainwater Collection System and Costs 

There are several different types of rainwater collection systems available, and each one varies in price, function, and capacity. You can pick out a simple rainwater collection system that features barrels that you sit out in the open to collect rainwater that runs off your roof. 

There are also much more complex rainwater collection systems that involve installing pipes that go from your root down underground and store in below-surface tanks. The most common system is the one that uses the rooftop harvesting method, and a brief description with prices are: 

Dry System

A dry rainwater collection system is just a bigger version of a traditional rain barrel. This system utilizes a big storage tan that you place close to the house. The water will flow from your seamless gutters directly into your storage tank. The system gets its name because the pipes go dry between rainfalls because water will flow straight into the tank. The largest cost factor for this rainwater collection system is the storage tank. The price varies based on storage material and capacity, and a 5,000-gallon polyethylene tank will cost just over $2,000. 

One of the biggest benefits of this type of rainwater collection system is how simple it is. The pipes go straight to the tank from the gutters, and they empty themselves in the process. This means that there will be minimal maintenance. However, they also involve putting tanks or barrels very close to your home, and this could be an aesthetic issue. This rainwater collection system starts at $1,000 and goes up to $5,000. 

Rain Barrel

Using a rain barrel is the most simple rainwater collection system you can have. The barrel will connect directly to your gutter’s downspout. It typically comes with a cover and a spigot at the base that makes it easy to access the water. Raising your barrel above ground level will allow gravity to push the water out when you need it. 

Your rain barrel will cost between $120 and $160. Some people could have an issue with having the larger barrels right up alongside their homes, but you can get a decorative rain barrel to match. Some people use them for DIY projects for outdoor furniture. You can paint the exterior and let a plant grow on top to enhance your rainwater collection system looks. 

Wet System

A wet rainwater collection system is much more complicated than the other two main types. When you install this type of system, you bury the pipes underground. All of your gutters will eventually feed into this underground system. The pipes will fill with water until there is enough water to spill over into your storage tank. The systems are called wet rainwater collection systems because the pipes are constantly filled with water unless you manually try to empty them. One large benefit is that the pipes get hidden, so they don’t interfere with your home’s design aesthetic or color scheme. The pipes are vulnerable to problems like debris accumulation or bug infestations, so you will need regular maintenance and good filters. 

Since a main component of this rainwater collection system is underground pipes, it costs much more than a rain barrel or dry system. Your costs will fluctuate based on the amount of pipes you have to lay. You’ll pay a contractor between $45.00 and $75.00 an hour for this work. 

If you want a 5,000-gallon tank with a sprinkler system included, you’ll pay between $2,500 and $4,500 to install the sprinkler system or irrigation system. This takes between 24 and 32 hours. Your steel storage tank will cost around $4,000, and a water treatment system will cost between $2,500 and $3,000. You also have to add excavator rental for a few hours at $440 to $750 to dig your hole for your tank. This brings your wet rainwater collection system cost up to around $12,000. The average cost range starts at $8,000 and goes up to $15,000. 

How to Build a Barrel Rainwater Collection System – Step-by-Step

This quick step-by-step guide will help you build a small and simple barrel rainwater collection system. You can DIY without a professional, but you should call in a professional for more complicated jobs. 

First Step – Prep Your Barrels

Thoroughly rinse out your three barrels on the outside and inside. Turn them upside down and allow them to drain and dry out. On the bottom of each barrel, get a paint pen and trace an opening for the downspout flex elbow connector. Get a jigsaw and cut it out. This is where the rain will flow in from the roof. Get a hole saw and cut out a hole for any overflow at the top of your barrel on the left side. This will prevent damage to the barrel if it gets too full. 

Second Step – Attach Your PVC

Measure and cut out your PVC pipe to create a “w” shape pipe system. Three pieces will be 3 ½-inches, two pieces will be 8-inches, one piece will be 20-inches, and one piece will be 10-inches. Lay your barrels down on their sides and create a skeleton that lays out how the PVC parts will connect at the bottom of the barrels. 

This PVC pipe shape will let the water flow from your first barrel up to the other barrels. Add plumbers tape to the threads of your connectors before screwing them into the threaded openings on all three barrels. Prep all of your PVC parts using PVC cleaner before gluing the pieces together with PVC cement. 

Third Step – Create a Barrel Stand

Get an outdoor-friendly wood like cedar to create a barrel stand. You can use 2x4s for the frame and the top of the stand, 1x6s as a border, and 4×4 posts as legs. Get 3-inch outdoor wood screws to attach everything together. Cut holes in the stand where your PVC pipes will go. You can also purchase a ready-made stand if you’re not a DIYer. 

Fourth Step – Attach Your Plumbing to the Barrels

Turn your barrels upside down and align your PVC connectors with the holes you put in your stand. Get PVC cement and use it to glue the pipe into place at the connectors under the stand on your rainwater collection system. 

Fifth Step – Secure Gutter Pipes and Overflow

You can make an overflow valve using two elbow joints and a length of PVC. Glue it into the hole you created in the left side of your first barrel. Attach a flex elbow from the gutter’s downspout into the hole in the top of your first rain barrel. Use silicone to lock it into place to keep everything watertight. The overflow should direct water away from your home. 

Six Step – Attach a Hose

When it’s time to water your plants, attach a hose to the spigot on your rain barrel. You can put large potted plants, shrubs, or trees in front of your rainwater collection system if you want to create a more aesthetically-pleasing look. Leave enough space to get to the spigot. 

3 Building a System
Labor costs can make up a decent portion of your total rainwater collection system costs, so you can save a lot by doing it yourself. However, more complex systems will require professional help.
Rainwater Collection and Storage, Bertschi School by Joe Wolf / CC BY-ND 2.0

Installation Considerations for the Different Rainwater Collection Systems

Before you install your new rainwater collection system, you’ll need to figure out what size storage tank you need. Once you do, you’ll have to set aside the right amount of space for it. The tank size needed will vary based on how much rainfall your planting zone gets and how much space you have available. If you get a 5,000-gallon polyethylene tank, you’ll spend just over $2,000 in most cases. 

For dry systems, you’ll have to put them right by your home. You can install a wet rainwater collection system further away from your home or building. A rain barrel should sit right under your downspout. Screens aren’t a must, but they are useful for preventing leaves and debris from getting into your collected rainwater. Filters also aren’t necessary if you plan to use your system for irrigation. However, you will need them if you want to use the rainwater for household items like bathing or cooking. 

Adding in an irrigation will significantly increase your rainwater collection system total. The elevation and location of your irrigation area relative to your new collection system will also factor into your costs. On average, installing an irrigation system will run between $2,500 to $3,500 on top of your other project costs. 

Labor Costs

The company you purchase your tan from could also provide installation services. However, a landscaper could also be able to install your rainwater collection system. The average project requires your contractor to prepare the area for your tank, connect the tank to your downspouts, and connect the tank to any exit points, pipes, or the pump. 

On average, your landscaper will charge between $45.00 and $75.00 an hour for this project. Installation time can vary based on your project’s scope and size. Installing an irrigation or sprinkler system for a wet setup will add between 24 and 36 labor hours, and this can increase your project costs by $2,000 to $3,500 for labor alone. A wet system also needs excavation to dig the hole to bury your storage tank. You’ll have to pay for any excavation equipment and the operator, and the project would most likely cost between $440 to $760 for three hours. 

Maintenance Prices

You will need to perform regular maintenance on your rainwater collection system. Filters and gutters do need to get cleaned periodically, and you should regularly inspect any components to ensure each part stays in good working order. You can do this yourself or have a landscaper come out and take care of it when they perform your routine yard maintenance. Landscapers will charge by the hour, and you want them to check your system each season. Take a few minutes to visually inspect the rainwater collection system after any rain to look for clogs in the filters. 

Additional Considerations for Your Rainwater Collection System 

Your rainwater collection system won’t be federally regulated. However, there may be local laws you have to abide by that regulates capturing rainwater. Most areas in the United States do allow you to freely harvest rainwater, but not each place will let you use the rainwater as potable water. Always check with your local laws before you install any type of rainwater collection system. 

If you want to connect your rainwater collection system directly to the city’s public water supply, double-check with your local regulations. Some municipalities won’t allow you to do this. Those that do could require you to apply for and purchase special permits. You’ll also want written consent of the local water supply system’s operator. Before you install the system, check with your local government. 

Harvesting rainwater isn’t the only way you have available to you to save water. You can make an effort to do other things like installing low-flow toilets during your next bathroom remodel, take shorter showers, water the lawn in the evening and morning, wash full loads of clothes only, use drip irrigation systems, and don’t overwater your plants. 

Depending on your location, you could get a tax incentive or two for installing your rainwater collection system. Deductions, tax credits, or exemptions could be available on a city or state level. Contact your town or city’s municipal offices and check your local guidelines. If there are tax incentives, they can walk you through the process of applying for them. 

Where to Find Rainwater Collection System Installers Near You 

If you don’t think that you can take on this project on your own, you can hire a professional company to come in and do it for you. This will increase your labor costs, but it will ensure that it’s installed correctly. You can start your search here: 

Frequently Asked Questions 

4 Rainwater Collection System FAQs
If you decide to contact local professionals to have them help with this project, make sure you ask questions to get a better understanding of the scope of the project. This way, it can help you understand the costs better too. 
Rain collection by Matt Baume / CC BY-SA 2.0

1. Is it illegal to collect rainwater?

In most parts of the United States, it’s perfectly legal to collect rainwater on your own property if you plan to use it to water your garden and lawn. However, it could be illegal to collect it to drink. Always check with your local ordinances before you install one. 

2. Can you scale your rainwater collection system?

Yes. It’s possible to scale your system to your needs. If you only have a small yard that you need to use the rainwater for, you could get away with a rain barrel. Larger yards will need bigger storage containers to hold more water. 

3. Is it safe to drink rainwater?

Untreated and unfiltered rainwater can contain contaminants like bacteria that can be bad for you if you ingest them. You’d need a very elaborate and properly maintained treatment system to be able to safely drink any rainwater you collect. Additionally, it’s illegal in several areas. 

Bottom Line

Rainwater collection systems can be very expensive, and this is especially true if you want a larger and more complex one. We’ve outlined the biggest factors to consider when you’re deciding on the system you can comfortably afford that holds enough water for your needs. You can use this guide to put together a rough estimate to take to your local landscapers and get the project started. 

Rainwater Collection System 1 Rainwater Collection System 2

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