First Flush Devices

The results of water quality tests. First flush verses no first flush.

The center pipe is a " first flush device ". It contains the first few gallons of rain water that have a higher bacteria content and solids that may create sediment in your rain water harvest system.


The effects on water quality are non-existent if your intention is to drink the water.

Our subjects were one home with half round gutters, a high quality gutter screen and no first flush and a home with regular ogee style gutters, no screen, but a first flush device.When using a standard test kit used to detect coliform bacteria we found that tanks connected with first flush devices and those without both had contamination. Coliform bacteria are those nasty little critters that make you have to run to the bathroom.
We used kits supplied to the missionary teams at www.peacewater.org to test two rain water harvesting systems installed in Southern California. The test was a simple pass or fail test. If the bags turned black, they were unfit for human consumption. Our subjects were one home with half round gutters, a high quality gutter screen and no first flush and a home with regular ogee style gutters, no screen, but a first flush device.

First flush devices are effective at minimizing sediment in rain tanks.

I always recommend a first flush device as part of a complete system. In this economy I am sensitive to the economic realites and I suggest the customer start with as large a tank as they have space for, as the MATH usually overwhelms are homeowners ability to store water.

By that I mean to make rain water harvesting be practical you need larger storage systems, to make it through dry months. However, few homeowners have the real estate, or space, to store the amount of water that comes off your roof. Therefor, the amount of water coming off your roof will be greater than the average ability to store.

That basic equation again; if you have ten inches of rain per year and you have one thousand square feet of roof your yield of rain water will be about 7,300 gallons per year ( and 7,300 gallons per year is 20 gallons averaged per day over 365 days ). So, a storage system of about one thousand to three thousand gallons seems optimal for a home in a climate that gets ten inches of rain per year. As a large above ground system may between one a five thousand dollars my suggestion is that the homeowner look at their rain water harvesting system as modular; get the largest tanks and best rain gutters you can afford and add a pump, first flush, gutter screen later if that is required due to budget constraints. If you " daisy chain " multiple tanks together be sure to offer the clients optional ball valves between each tank. This allows individual tanks to be cleaned or moved without having to drain the whole system.

Then we let the bag sit at room temp for two days. The results were disconcerting, because the tech team at www.peacewater.org are trying to see if this technology can be used to provide drinking water for people who have no reliable source of clean water.

The results of the Hach tests were showing coliform bacteria in both samples. So we proved the water is unsafe to drink without filtration, but technical data done by other entities indicate that first flush devices help reduce other types of measurable contaminations including solids that create sediment inside large rain cisterns or tanks.
For emergency filtration of rain water for drinking I recommend you purchase a Sawyer type filter and have clean buckets ready in kit, or have stove and fuel to boil the water.


As far as the water quality of rain water for gardening it seems obvious that the plants love the chemistry of the bird dropping and other biomass that make up the sediment of a large rain tank. My final opinion is that the priorities should be having large tanks first, a filtration system secon and a distribution system, like a pump, last.

There are companies producing high quality first flush devices for sale such as www.rainharvesting.com. I really admire their under ground first flush diverters and the technical data they have assembled.

Rain Water Harvesting; The Math

The math on rain water harvesting is very important if people are to embrace this technology. A main stumbling block in my sales is that people assume that there is not enough rain in Southern California to warrant investment in the harvesting of rain water. Allow me to demonstrate that this thinking is wrong.

Please consider;
1000 square feet of roof yield 623 gallons of water per inch of rain.
The  whole calculation goes like this; Roof area (ft square) X rainfall ( ft ) X 7.48 gal/ft+ total rainwater ( gal ).

For example, if you want to calculate how much rainwater in gallons falls on your 55-by-80-foot ( 4400-square-foot) lot in a normal year where rain fall averages 12 inches. the calculation would look like this;
4,400-square-foot catchment area X 1 foot of average rainfall X 7.48 gallons per cubic foot = 32,912 gallons of rain falling on the site in an average year rain.
Credit on the above data.


So one of the key concepts is to live within your site's water budget.

That means using your properties annual average rainfall as the basis of what plants get used in your yard. Excess water collected from the roof is then used ( in theory ) to water the plants that require more than the natural rainfall ( such as fruit trees and vegetable gardens ) so that for the ornamental landscaping no further use of city water is required to have a lush and attractive yard.

Consume less water on your property than falls on your property in an average year of rainfall.

Rain water helps powers this food garden in San Clemente Califonia. 

Currently some cities offer rebates towards the implementation of rain water systems. You can help facilitate this by contacting your representative and letting them know your town wants those rebates too! Solar is far more expensive and out of reach for many into today's harsh Southern California economy.

Please consider the following;

1. Rainwater ( and hail, sleet and snowfall ) is delivered to us free of charge, eliminating the need for costly distribution systems. Did you know that 20% of all energy consumed in California is used to transport, treat or store water?
2. Rainwater is the highest-quality source of irrigation water
3. Rain water is salt-free and can help flush plant damaging salts from the root zone in alkaline soils
4. Rainwater is a natural fertilizer containing sulfur, beneficial microorganisms, mineral nutrients, and nitrogen
5. Rainwater harvesting helps reduce utility bills
6. Rainwater harvesting reduces flooding by reducing flow to streets and storm drains
7. Rainwater harvesting reduces nonpoint-source pollution of stormwater
8. Rainwater harvesting provides a water source when well, surface, or municipal water is contaminated or unreliable ( such as after a major Earthquake )
9. Water harvesting helps utilitys reduce summer peak demands for water and reduces the volume of wastewater that needs to be treated at water treatment plants
10. Water harvesting is fun! The food from my garden tastes better than store bought food and we have emergency water storage

This is our own family  rain garden. This year we produced onions, potatoes, strawberries, rosemarry, mint, thyme, basil, oregeno, sage, carrots and more. We just planted peppers and tomatoes for the summer growing season.

Using a three thousand square foot home in Yorba Linda California as  a model we conclude that if that home harvested just one third the home into a rain tank or cistern system they would have 8,700 gallons yield per year.  These are facts. Here is a link to the rainfall data; click here. That is 23.83 gallon of  fresh water available for use every single day.

That is why larger systems make sense.

More from our own raised flower beds this year;

lettuce and oregeno

Potatoes ( foreground ) mint and green onions

Tomatoes and fresh basil from the garden with mozzarella cheese ( yummy! )

Rain Water Harvesting Storage Tanks Mitigate The Big One?

Part of these blogs posts objective is to share some of the information I learn, being in the water business. The other part is to sell rain barrels. I do believe that you should consider the following information irregardless of your intentions about buying rain barrels. If you live in California, please read;

Currently there are raging debates about the delta Smelt, the California levee system and if a canal or aquaduct should be created to bypass the fragile levees. How does this effect Southern California people? Well, imagine water faucets in your home that don't work.

We know that a major Earthquake will eventually happen, and that it could destroy the levee systems and allow sea water to contaminate our drinking water. Imagine 20 million people in Southern California without drinkable water. We also know that major, even historic cuts to Californias water infrastructure loom in the immediate future. There are no plans to address any of these issues, and given the feckless nature of our political class, things will only get worse.

Of course, my interest is in getting people to change the way they think about rain and rain gutters. I confess I have an agenda. I asked Jeff Helton, the regional sales manager at Bushman rain tanks what it would take to get the average Southern California person serious about collecting and storing rainwater and his answer made sense. He said, " this tract that I live in in Murietta Valley almost didn't get built because they could not get an allocation of water. New rules say that before you can build you must plan for the water. Once they start building again the water rationing will return in full force and get people off the fence about rainwater harvesting. "

Then, as I usually do I did some research and found that in an average year, water shares were issued for eight times more water than existed. Check it out yourself;

The reality is, poor planning, incompetence and a dismal failure of leadership has set California up for a epic disaster and everybody has to do their share to reduce and conserve water, for our own sakes. We have to have our own micro-infrastructure ( our homes ) yield water to decrease the dependence on a government that fails to plan, fails to act or is planning on failure. They seem to prefer endless crisis orientated realities rather than meeting these challenges head on. We all agree that the economy will not be sound until there are homes being built, but the catch 22 is that in reality there are very few homes that can be built with our infrastructure.

key thoughts: micro-infrastructure. perma-culture. self-reliance



Get this, when you read about foreign banks and Wall Street tycoons getting trillions in so called bailouts remember; " Next year water infrastructure projects and programs are expected to see massive budget cuts as President Obama has proposed slashing infrastructure spending at the Environmental Protection Agency (EPA) and the U.S. Army Corps of Engineers; the Drinking Water State Revolving Fund (SRF) will see nearly $400 million cuts and the Clean Water SRF will be cut nearly $600 million; according to Lisa Jackson, the EPA administrator, these cuts in SRF budgets reflect a return to a more "sustainable level"; states worry that cuts will make it difficult to fund future infrastructure upgrades; reports have shown that the United States faces a $500 billion shortfall for water infrastructure funding over the next twenty years ".
Check it out here.

If the levee situation is not addressed, if more storage is not built then there can be no new construction in  California. As the above text from homeland Security indicates, the money got spent elsewhere. These decisions are going to result in massive economic hardship and potential loss of life when the big one hits and those of us in Los Angeles look to the feds to save us, like they did in Katrina.

Every home in Southern California needs to be equipped with a rain water harvesting system with at least 1000 gallons of capacity. It is socially responsible to get rid of your grass, plant native plants that are conditioned for our desert climate. Every home should have a basic gray water system where the water from their laundry discharge is fed through pipes that water food bearing gardens.
I say 1000 gallons minimum based on a typical rain year in Anaheim. You need a large capacity to carry over through dry months, to be prepared for a water disaster. The math suggests that if 1000 square feet of roof were harvested, in a typical rain year in Anaheim California that roof would yield 8700 gallons.

IMPORTANT VIDEO! PLEASE TAKE A FEW MINUTES TO WATCH.

The Cycle of Insanity: The Real Story of Water from Surfrider Foundation on Vimeo.



Supporting links;
http://www.greendiary.com/entry/earthquake-in-california-could-cause-another-katrina-in-next-50-years/
http://www.californiaprogressreport.com/site/node/8640
http://www.homelandsecuritynewswire.com/water-infrastructure-budgets-see-massive-cuts-2012