Home > Rain, Rain Harvest > First Flush Rain Harvesting Setup

First Flush Rain Harvesting Setup

My interest in rain harvesting arose out of my efforts to solve my irrigation problem at the orchard. The orchard lot does not have city water service hooked up. City water service is at the street and would necessitate the installation of a meter plus trenching some 200-plus feet to get the water to the orchard. I’ve had to deal with meter installation before so I know that City of Atlanta charges an outrageous $2,000 meter installation fee just for to put in a meter. That plus the installation of underground lines to get the water from the street to the orchard would probably cost close to $5,000 when it’s all said and done.

I then entertained the idea of getting a well dug. That also looked like it would be a costly proposition. Even worse, drilling companies don’t offer a guarantee that they will hit water. So if the first attempt fails, you still get charged for it and then you will get charge more for them to attempt another spot. Not to mention, a well would then also require electric service and that also did not exist on the lot and would need to be run from the street to the orchard, as well.

Due to the costs associated with the above two options, I began thinking about rain harvesting. After some thought, I determined that this option was not only the cheapest but was also the most-aligned with my pursuit for self-sufficiency. The orchard is about 1.5 miles from my house so I would either have to build a structure at the orchard to collect rain run-off from or I would have to do the collection at my house and then transport it to the orchard. I decided to start with the latter, since I needed water at my house for my garden anyways.

My house’s total roof area is approximately 2,500 square feet. Each square feet of surface area results in 0.60 gallons of rain water collection for every one inch of rainfall. This translates to a total of 1,500 gallons of rain for every one inch of rainfall if I harvest rain off of every gutter downspout:

2,500 square feet x 0.60 gallons/square feet/inch of rain = 1,500 gallons/inch of rain

Atlanta’s monthly rainfall averages about 4 inches, which means I can capture a whopping 6,000 gallons of water every month. This would provide plenty of water to satisfy all my irrigation requirements at my home and at the orchard during dry spells and all with just a one time expense of getting my rain harvesting setup implemented.

After some research, I finalized my rain harvesting setup to use the following:

I purchased the downspout filter and first flush diverter from www.rainharvest.com which happens to be located in about half hour from Atlanta in Cummings, Georgia.  Having a local resource really helped because it allowed me to go to their location and see all the products firsthand and get all my question answered.  The PVC pipe and parts was purchased from local Home Depot and Lowe’s stores.  Lastly, the 330 gallon IBC totes were purchased locally from an ad on Craigslist.

Once all the parts were obtained, I started on my first downspout conversion.  This is what the downspout looked like prior to the conversion.


I began first by removing the existing aluminum downspout.


Then it was time to install the Leaf Eater.




A top view of the Leaf Eater downspout filter.  It comes with a PVC adapter which allows the output end of the filter to join with a 4 inch PVC pipe.


The original downspout elbow is put back in place to route rain water from the gutter to the Leaf Eater.


The Leaf Eater is then installed flush under the downspout elbow with the use of screws.


Once the Leaf Eater is secured, it will also keep the downspout elbow in place.




I then installed the PVC adapter which came with the Leaf Eater to the bottom output of the Leaf Eater.


Next, I unpacked the contents of the First Flush Diverter kit.


From the kit, I began with the 4 inch PVC tee connector and the floating ball seat.


The floating ball seat is placed in one of the horizontal ends of the 4 inch PVC tee connector.


Then a 4.5 inch segment of a 4 inch PVC pipe is cut.


The 4.5 inch 4 inch PVC pipe is then inserted into the horizontal end opening opposite of the one already containing the floating ball seat.



The assembly is then slid onto the bottom output end of the Leaf Eater.


The floating ball seat must in the bottom end opening of the 4 inch tee connector.



Due to the location of this particular downspout, the downspout bracket which came with the First Flush Diverter kit is not suitable.  Instead, I purchased a 3 inch – 4 inch tie from Home Depot.


The tee connector is temporarily removed and the tie strap is nailed into place.

The tee connector is put back in place and the tie strap is tightened to suspend the tee connector in place.




Measurement is then taken from the inside of the bottom end of the tee connector to the bottom edge of the trim behind the downspout.


The measured out to be 75 inches.


A 4 inch PVC is then cut to provide a segment that is 72 inches, 3 inches shorter than the previous measurement.




Before the PVC pipe section is inserted into the tee connector, I verified that the floating ball seat is still in the tee connector and has not fallen out.


The 4″ diameter PVC pipe is then inserted into the bottom opening of the tee connector.   This PVC pipe segment will serve as the reservoir for the first flush system.


A 4 inch diameter 90 degree PVC elbow is then fitted to the bottom of the 4 inch diameter PVC pipe.



The place where the 90 degree elbow begins its bend is noted so that another tie strap can be nailed into the trim.   This bottom tie strap will hold the 4 inch diameter PVC pipe in place.  The 72 inch 4 inch diameter PVC pipe which serves as the reservoir for the first flush system will hold 4 gallons of water when full.  Water weighs about 8.35 pounds per gallon, so this segment of PVC pipe will weigh over 33 pounds when full so this bottom tie strap is needed to support this weight.


With the bottom tie strap in place the 90 degree elbow put back into place and the tie strap is tightened around it.


So far, all PVC connections have been dry fitted without adhesive.  However, adhesive must be used in the final connection of the 90 degree PVC elbow to the first flush drain assembly.  Without adhesive, this assembly will blow open from the weight of the water in the first flush reservoir.   As before, a 4.5 inch section of the 4 inch diameter PVC pipe is cut.  This section is used to coupled the 90 degree PVC elbow to the first flush drain assembly.  Adhesive must be applied to both ends of this coupling section.



Once the adhesive has set, the first flush drain assembly is opened by twisting counter-clockwise.  Once opened, the floating ball of the first flush assembly is inserted.


The first flush drain assembly cover is screwed back in place and the drain nozzle is opened by twisting the nozzle counter-clockwise.


A debris filter is inserted to prevent clogging of the first flush drain nozzle.


A washer is also placed into the nozzle.  A total of eight washers are provided in the kit.  The washers have drain holes of various sizes.  These washer are used to control the rate of drain from the first flush reservoir.  I chose to use the washer with the smallest hole.


The drain nozzle is put back in place.



Another 4.5 inch segment of 4 inch diameter PVC pipe is cut to couple and adapt the 4 inch first flush diverter opening to  a 2 inch PVC pipe which will drain to the IBC tote.





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