Wednesday, March 14, 2018

Rainwater not Desalination

Conventional wisdom is that people use about 100 gallons per day of water. My family averages less than 50, but maybe 100 GPD includes water use embedded in things we buy or use. About 350,000,000 people live in the USA. So adding the data on rainfall from this page, the Lower 48 receive about 100x the amount of water needed. That’s pure water desalinated and transported without any man made energy. Just need to be more efficient in collecting it.

That’s where rainwater harvesting comes in. Most every single-family home could collect enough water to meet the needs of the residents, especially when combined with graywater treatment and reuse. The technology is mature and reliable, and becoming more affordable every year. The process is specified in plumbing codes. The products are certified by independent third parties.

Friday, January 6, 2017

Rainwater Harvesting Grants for Nonprofits

The Community Foundation for Greater Georgia offers water (and energy) efficiency grants for nonprofits. The Grants-to-Green program has been very popular. It awards grants twice a year. For more information, click here: 

For religious organizations, Georgia Interfaith Power & Light,, offers energy efficiency grants, but not for water. Yet! Please contact and encourage them here!

They also offer rainbarrel workshops. For more information, click here.  Here's hoping that they don't use translucent rain barrels anymore!

Thursday, December 29, 2016

Rainwater Harvesting for Community Gardens

Another community garden is ready for the rain! We do some installations ourselves, but our goal is to teach contractors how to add rainwater harvesting to their portfolio of services.

Like many of these community gardens, this school takes water from a single downspout. A 4" pipe brings rainwater to an above-ground tank, which has a basket-style prefilter. Yes these require cleaning, but they are most popular. A typical rainstorm will fill the tank.

This project didn't use a pump, but most do.

Saturday, September 17, 2016

Drought Returns to Georgia

This the current condition in Georgia. We are again in a Level 1 Drought as of September 2016. The area under Moderate Drought or higher has doubled from 20% of the state last year this time, to 40%. No additional watering restrictions have been added so far.

What should I do?

We all want nice green lawns, but grass is the most easily replaced part of the landscaping. It's more important to protect trees and shrubs. However, the condition of the grass is a good indication of the moisture available to all the landscaping, IF WE WATER EVENLY.  So when you water, cover the whole yard!

There are various methods for conserving water in irrigation: some use weather data downloaded from NOAA. Others measure sunlight intensity, temperature, humidity, and the presence of rainfall. Others use soil moisture content. We will be experimenting with this, but my preference is always a direct measure of the desired result. So, moisture sensors. However, sensor quality can be highly variable no matter what kind, especially something mass produced for consumers.

And of course, collect rainwater! If drought levels worsen, there's a real possibility of a total outdoor watering ban. How can a rainwater system help? Even the worst droughts in Georgia are a 50% reduction of rainfall. Which means that most buildings can double their effective rainfall with a rainwater system, which should be enough to protect trees and shrubs.

Please contact Georgia Water Tanks for help protecting your valuable landscaping. Our primary business is supplying equipment to contractors, with design assistance and on-site support during installation and commissioning included. If you are a property owner and are looking for an installer, we can recommend several that are experienced installers. And we are always looking to train more!

Friday, April 29, 2016

Rainwater Harvesting Laws and Incentives - State by State

"Check your local laws before collecting rainwater. . . it's illegal in some states!" How many times have we heard that dire and vague warning. The truth is quite different. Click here to see the current laws for your state.

Saturday, January 9, 2016

Purain Filters USA

Our online partner and official web provider of prefilters RainHarvesting Supplies, has created a new online home for Purain Filters USA.  Check it out here:

6" Purain In-Tank Package

Wednesday, November 18, 2015

A Simple Design for Stormwater Compliance - New Homes

This design is for new single family homes, or small commercial properties, up to about 10,000 s.f. of impervious surface (rooftops and driveways). You will find that the cost is as low as any approved stormwater management method, plus you will collect about 20 gallons/square foot of impervious surface.

Sizing the Infiltrator Below-Ground Tank

You'll need 1 for every 1800 square feet of impervious surface.  If you have a fraction the round up (e.g. 4100 s.f. / 1800 = 2.27; you'll need 3)  The dimensions are 14' long x 5' wide. They can be buried 6" - 48" deep.

Infiltrator tanks do not require gravel backfill or other soil amendment, provided that the soil is no more than 70% clay. Interconnect the tanks with 1" - 2" flexible PVC.

In-Tank Prefilter

The 4" Purain filter is suitable for about 1800 square feet also. Plan on a filter in each tank.

This means that you will need a manhole for each tank. If you have 3-5 tanks and don't want so many manholes, then choose a single, larger, Purain HD for direct burial.


Pipe from the downspouts to the tank location with SDR 35 pipe. If you have multiple filters, you'll need a header at the tank to distribute the water.


A submersible pump with a floating filter intake will send the water to your irrigation system. A pressure-activated pump will start whenever the irrigation heads open, and also if you have a hose connection. They will also start and run continuously if you have a leak in your irrigation system. We can also synchronize the pump start with the irrigation controller. We can put a timer switch next to a hose connection. We like the second method a little better, but either can be best.

The pump will need a floating filter intake, as shown in the photo, to maximize water quality.

Standby Connection

Two common methods are a pressure regulating valve (PRV) or a solenoid valve. Either is acceptable in residential systems. Solenoid valve systems cost a little less conserve city water pressure better; PRV's are more readily available, last longer, and easier to service.

Standby Connection Protection

Most municipalities are currently requiring an RPZ backflow preventer or air gap at a standby connection, unfortunately. We have new evidence that the rainwater does not contain any known contaminants, and would love to discuss this with your plumbing inspector. We would recommend a dual check valve, if that is typically an acceptable level of protection for a residential irrigation system. Dual check valves can be buried, which makes them easier to install. RPZ backflow preventers must be installed inside, or in an above-ground insulated and heated enclosure. Air gaps require re-pumping and therefore waste energy.

Georgia Water Tanks provides design assistance and on-site installation supervision for all packages.