Rainwater Harvesting Systems, Inc.

A professionally installed rainwater system will include a collection system, adequate filtration, a holding tank, and distribution system.  Costs vary greatly between a small residential system and a large commercial system as well as between the cost for above ground and under ground tanks. 

For Reference

• A small residential system, collecting water from 500 sq. ft., with a 1,000 gallon above ground plastic tank.  Starting at $2,500 installed.
• A large residential system, collecting water from 2,500 sq. ft., with a 5,000 gallon above ground metal tank. Starting at $10,000 installed.
• A small commercial system, collecting water from 8,000 sq. ft., with a 20,000 gallon above ground metal tank. Starting at $25,000 installed.
• A large commercial system, collecting from 12,000 sq. ft., with 25,000 below ground storage tank. Starting at $75,000 installed.

Tanks
When considering the cost of a rainwater system, the tank is a large portion of the total cost.  While everyone would like to have enough storage so that the tank never overflows, many factors come into play such as water demand, rainfall patterns and cost.

A general rule is to multiply your catchment area by 2 so that you can collect 4 inches of rain in one week.  For example a 2,000 sq. ft. home would be paired with a minimum 4,000 gallon tank.  A 10,000 sq. ft. building = minimum 20,000 gallon tank.  In cases where a rainwater system is the only source of water or there are extended droughts, a larger holding tank is required.

The cost of a tank depends on its size, quality, material, and site preparation.  Shipping can also add significantly to the entire cost of placing a tank.  Once you know the approximate size of tank you'll need, choose above or below ground and your preferred material.