Rainwater harvesting is one of those ideas that sounds too good to be true—free water falling from the sky, just waiting to be collected and put to good use. But here’s the question everyone really wants answered.

Is it actually worth the effort and expense? 

I’ve spent nearly 20 years in this industry, answering thousands of questions from homeowners, preppers, and businesses who all want to know the same thing—will rainwater harvesting save them money?

Why Are More People Harvesting Rainwater?

The interest in rainwater collection has exploded in the last decade, and it’s not just about hugging trees (though sustainability is a big factor). People are tired of rising water bills. Municipal water rates keep climbing, droughts are becoming more frequent, and cities are placing restrictions on outdoor water use. If you have a thirsty garden, a large lawn, or just want to cut down on utility costs, harvesting rainwater makes sense.

For some, it’s about self-sufficiency.

Preppers and off-grid homeowners don’t want to rely on city water. Others are looking ahead, knowing that infrastructure issues and water shortages aren’t going away anytime soon. And then there are people like me—obsessed with efficiency, conservation, and making the most of every drop that falls on their property.

How Much Water Can You Collect? (And How Much Do You Need?)

So, you’re thinking about collecting rainwater—but how much can you actually capture? And just as importantly, how much do you really need?

The answer depends on a few key factors: your roof size, local rainfall, and how you plan to use the water. Let’s break it down.

Understanding Your Water Collection Potential

There’s a simple formula to estimate how much water you can collect:

1 inch of rain = 0.62 gallons per square foot of roof

That means if you’ve got a 2,000 sq. ft. roof, here’s what you can expect in different climates:

This is why rainwater harvesting makes sense everywhere. Even in dry regions, you can still collect thousands of gallons per year.

To check your exact rainfall, head over to US Climate Data and look up your area.

Common Uses for Rainwater (And How Much You’ll Save)

Irrigation: Gardens, Lawns, and Potted Plants

Your lawn and garden account for up to 50% of household water use in the summer. Instead of paying for city water, why not use what falls from the sky?

• 1,000 sq. ft. lawn = 620 gallons per inch of rain

• Raised garden beds (200 sq. ft.) = ~125 gallons per inch of rain

• Potted plants = A single rain barrel (50-100 gallons) can keep them happy for weeks

For gardeners, a single rain barrel can save you $20-$40/month on water costs during peak growing season.

Helpful Resource -> What Is A Rainwater Garden?

Toilet Flushing & Laundry

An average household flushes 18.5 gallons per person per day. That’s over 5,500 gallons per year per person! Rainwater can cover this easily.

• A 1,000-gallon cistern could supply 2-3 months of toilet flushing

• Laundry machines use 15-30 gallons per load, making rainwater a great option for reducing municipal water use

Using Rainwaters To Flush Toilets - Drexel University

Drinking & Cooking (With Proper Treatment)

Yes, rainwater can be made drinkable—but you’ll need filtration and disinfection to remove contaminants from the roof.

• Simple filtration (charcoal & sediment filters) = Good for washing produce, but not safe for drinking

• Advanced filtration (UV light, reverse osmosis) = Can make rainwater safe to drink

• Cost to treat drinking water: $200-$1,500 upfront, but eliminates the need for bottled water

Emergency Storage: Backup Water for Wildfires & Disasters

Photo Source -> Desert Research Institute

Rainwater storage is a lifesaver in emergencies. Whether it’s wildfire protection, drought, or water shutoffs, having a backup tank means you’re prepared.

• Fire Protection: A 1,500-gallon cistern gives you enough water to douse embers or help firefighters

• Drought Readiness: If your city imposes water restrictions, your stored rainwater keeps you self-sufficient

Greywater Systems: Connecting Rainwater to Your Home’s Plumbing

Some people go all-in and connect rainwater to their plumbing.

• Gravity-fed systems can supply toilets, laundry, and outdoor taps with minimal pumping costs

• Pressurized systems with pumps provide full household integration

• Cost range: $2,000-$10,000 depending on complexity

How Much Does It Cost to Set Up a Rainwater Harvesting System?

The answer depends on how much water you want to store and what you plan to use it for. A simple rain barrel setup can be as cheap as $50, while a fully integrated underground cistern can set you back $15,000 or more. 

The average water bill in the U.S. is $73/month (~$840/year), but prices vary widely:

• Low-cost areas (Midwest, South): $1.50–$3 per 1,000 gallons

• Moderate-cost areas (Texas, Colorado, East Coast): $4–$7 per 1,000 gallons

• High-cost areas (California, Nevada, Arizona): $8–$15 per 1,000 gallons

Cost Breakdown for Different Systems

Small Systems (Rain Barrels: $50–$600)

• The most affordable option for homeowners.

• Quick ROI—can pay for itself in as little as one season if you water your garden regularly.

• Downsides: Limited storage capacity; can overflow quickly.

Get your hands on our $449 75 Gallon Rain Barrel pictured above.

• 75 gallon storage capacity

• Small foot print 20" x 24" x 42"

• 2"od diameter overflow port on each side

• 2"od diameter bottom port on each side

• Built-in debris filter

• Garden hose shut off valve

• Child safe design

• 100% recycled plastic

• UV-resistant polyethylene

• Multiple units can be connected in series

Mid-Size Systems (Above-Ground Cisterns: $1,000–$5,000)

• Ideal for larger gardens, fire protection, and partial home integration (toilets, laundry, irrigation).

• Requires more space and may need a pump for higher pressure.

• ROI depends on how much municipal water you’re replacing.

-> Shop Our Above-Ground Cisterns 100 to 5050 Gallons

Full-Scale Systems (Underground Cisterns: $5,000–$15,000+)

• The most expensive but offers whole-home water independence.

• Buried storage = no space lost in the yard and protection from freezing.

• Can be connected to your home’s plumbing, requiring professional installation.

• ROI is longer (10+ years) but savings increase over time as water rates rise.

Pro Tip: If you’re on a budget, start with plastic or repurposed barrels and upgrade later.

The Most Cost-Effective Way to Start Rainwater Harvesting

If you’re just getting started with rainwater harvesting, don’t overcomplicate it. You don’t need a high-end underground cistern or an expensive filtration system to see savings. The most budget-friendly approach is to start small, learn what works for your home, and scale up over time.

Start Small & Scale Up

Begin with a single rain barrel. This is the way we all got started with rainwater harvesting, including myself.

A basic 50-100 gallon rain barrel is the simplest, lowest-cost way to start collecting rainwater. It’s an easy DIY project that can pay for itself within a year or two.

• Cost: $50-$250 (or free if you repurpose a food-grade barrel)

• Setup Time: Under an hour

• Savings: Can replace up to 1,200 gallons of water per year for gardens, saving $20-$60 annually

• Best Use: Watering plants, washing tools, car washing

Pro Tip: If you're on a tight budget, check with local municipalities—many offer free or discounted rain barrels as part of conservation programs.

Is Rainwater Harvesting Right for You?

Photo Source -> University System of Maryland

So, after breaking down the costs, savings, and setup options, is rainwater harvesting worth it for your home?

The short answer: Yes, but only if you approach it the right way.

If you expect to slap a barrel under your downspout and cut your water bill in half overnight, you’ll be disappointed. But if you start small, scale up smartly, and match your system to your water needs, you can save money, increase self-sufficiency, and reduce your reliance on municipal water.

Who Benefits Most from Rainwater Harvesting?

• Homeowners in High Water Cost Areas – If you live where water rates are sky-high (California, Arizona, Texas), a rainwater system can pay for itself faster.

• Gardeners & Lawn Enthusiasts – Even a single rain barrel can save hundreds of gallons per month in irrigation costs.

• Preppers & Off-Grid Homeowners – Rainwater collection is a crucial backup system in emergencies.

• Eco-Conscious Households – Reduce stormwater runoff and cut your environmental impact.

• DIYers & Budget-Savvy Homeowners – You can start for under $100 and scale up as needed.

Helpful Resource -> What Are The Benefits Of Rainwater Harvesting

Best Way to Start? Keep It Simple.

Step 1: Install a single rain barrel (50-100 gallons). Pays for itself in 1-3 years.
Step 2: Expand with multiple barrels or a small above-ground cistern (200-500 gallons).
Step 3: If long-term savings matter, invest in a larger system for household use.

If you live in an HOA-regulated area, opt for slimline tanks, underground cisterns, or hidden storage to stay compliant.

Ready to Start? Explore Rain Barrels & Cisterns for Your Home

The sooner you start, the sooner you stop paying for water you don’t need to.

Check out our selection of high-quality rain barrels and cisterns – built to last, easy to install, and designed for maximum savings.

Browse Rainwater Collection Systems Now