Rainwater harvesting system cost by tank size, above ground and do it yourself
Rainwater harvesting system cost by tank size depends first on whether a tank sits above ground or below it, and only second on how large the tank is. Plastic Mart, a manufacturer reseller, lists an above ground tank a homeowner can buy and install without a professional at 979.99 dollars for 500 gallons, 1,631.96 dollars for 1,000 gallons, 2,335.64 dollars for 2,500 gallons, 5,990.69 dollars for 5,000 gallons and 15,799.99 dollars for 10,000 gallons, every price fetched directly off the tank own product page this month.
Prices are the tank alone, above ground, do it yourself installation with no excavation, current as of the access date.
Show the numbers
| 500 gallons | 979.99 |
| 1,000 gallons | 1,631.96 |
| 2,500 gallons | 2,335.64 |
| 5,000 gallons | 5,990.69 |
| 10,000 gallons | 15,799.99 |
Dividing each of those 5 prices by its own capacity, an arithmetic this article performed rather than a figure either company states, gives 1.96 dollars a gallon at 500 gallons, dropping to 0.93 dollars at 2,500 gallons, the cheapest size per gallon on the list, then rising again to 1.58 dollars at 10,000 gallons. A bigger tank is not automatically cheaper per gallon.
Underground tanks cost more before installation even starts
Poly Tank Sales, a second and independent reseller, lists the same Norwesco brand built for underground installation, tank alone, stated plainly as not installed. Its prices run 1,780 dollars for 550 gallons up to 19,700 dollars for 10,000 gallons, with a 2,500 gallon underground tank costing 6,889.99 dollars.
Prices are the tank alone, underground, before excavation or installation labour, current as of the access date.
Show the numbers
| 550 gallons | 1,780 |
| 1,175 gallons | 2,670 |
| 2,500 gallons | 6,889.99 |
| 5,025 gallons | 16,309.99 |
| 10,000 gallons | 19,700 |
At the 2 sizes that exist in both lists exactly, 2,500 gallons and 10,000 gallons, dividing each company own price by its own capacity, an arithmetic this article performed by fetching and reading both live price lists directly rather than any figure either company states, shows the underground tank costing 2.76 dollars and 1.97 dollars a gallon, against 0.93 dollars and 1.58 dollars a gallon for the above ground tank at the same 2 sizes. That gap holds before a single dollar is spent on the excavation an underground tank still needs.
This is the site own calculation, dividing each company price by its own stated capacity, at the 2 sizes that exist in both price lists exactly. Source 1 supplies the above ground figures, source 2 the underground figures.
Show the numbers
| 2,500 gallons, above ground | 0.93 |
| 2,500 gallons, underground | 2.76 |
| 10,000 gallons, above ground | 1.58 |
| 10,000 gallons, underground | 1.97 |
A rebate that can cut either route, and where the rest of the cost and the law live
San Antonio Water System pays 1 dollar back for every gallon of storage bought, with a 500 gallon minimum, up to a maximum rebate of 2,000 dollars for a tank of 2,000 gallons or larger, a program that by itself refunds more than half the price of the cheapest above ground tank in this article. The tank price alone still leaves out pumps, filtration and gutters. The Environmental Protection Agency stated in 2013 that a typical cistern runs 1.50 to 3.00 dollars a gallon before those extra parts, and the Texas Water Development Board, in a 2005 manual, prices a roof washer that filters debris before it reaches the tank at 50 to 800 dollars, and a pump and pressure tank together at 385 to more than 1,100 dollars. Rebates vary by state and by utility, covered in the site own article on rainwater harvesting rebates by state. Whether a household may even collect rainwater at all is a separate legal question, covered in the site own article on rainwater harvesting and water rights law. The full life cycle cost of a complete system, filtration included, is covered in the site own article on rainwater harvesting system cost and savings.