What are you going to use the water for?
Tank size is often determined by what you use the water for. We can use 70% of our water for irrigation!
How much can you collect?
In Central Texas, where we get about 32” of rain in a normal year, a one story 2000 sq. foot house can collect 35,000 gallons of rainwater a year. Don’t design a system that tries to direct that much rain into a 300 gallon tank!
How much space do you have?
Lots of times space is a limiting factor. Are there trees that prevent installation of large tanks? How high are the eaves on your house? Seven foot tall tanks work well for eight foot eaves. Is there a fence in the way? We’ve temporarily removed fencing to get tanks into place.
Are you applying for a rebate?
Many municipalities offer rebates from $0.50 / gallon up to $1.00 / gallon. In some instances you need to be pre-approved before you purchase and install your tank.
Are you part of an HOA or POA?
Great news! In 2013 the Texas Legislature passed a law prohibiting HOA’s from banning rainwater harvesting systems. They might limit the location, but they must allow rain-water tanks. If your HOA is unfamiliar with this law, tell them to see Texas Property Code Sec 202.007.
Installing Your System
Choosing a base
The tank needs to be installed on a solid base supporting the entire bottom. We recommend crushed granite or a similar base. Limestone block, brick, or pavers can also be used. The simplest thing to do is get some treated landscape timbers and form a square about a foot wider than your tank. Fill with 2”- 3” of crushed granite and tamp down. The tank can sit directly on the crushed granite. Of course, a concrete pad also works! Keep in mind water weighs 8.3 pounds per gallon, so a 2500 gallon tank weighs over 10 tons when full!
Moving the tank into place
Large tanks slide easily across 2 X 4’s, or better yet, PVC pipes. Tanks can also be tipped on a bottom edge and rolled. Do not lay a large tank on its side and roll it!
Positioning of fittings
Generally, don’t position the overflow above the outlet. If you decide to plumb the overflow, the pvc pipe will come down where your outlet is! The overflow should channel water away from the tank and house towards a low lying area.
Important!!! These are threaded on both the inside and outside. You will only be able to screw things into the inside of the bulkhead. The outside threads are reversed thread and only accept the locknut. Therefore a 3/4” bulkhead accepts a 3/4” spigot, for example.
Painting the PVC
Choose a metallic gray spray paint to make the overflow and inlet look like metal. Rustoleum™ makes a good product available at The Home Depot.
Securing the top
The top of your tank needs to be secured in place so it doesn’t blow off. Four self tapping sheet metal screws should be included with your tank. We recommend pre-drilling the holes about an 1 1/2” from the edge. There is a lip at the top of the tank.