Rain Water Collection

My Dad installed whole-house rain water collection in 2011 after a fierce Texas drought caused him to worry about his well water supply. His includes a pump and complex filtering and runs right into his tap. Probably 10 or 15 thousand gallons!
I didn’t want a whole house version but I did want a backup supply readily available and I wanted to water my garden. Under my back deck appeared to have sufficient room for several smaller tanks.
So I made a plan to see what might be possible.
The free space under the deck limited me to 1,000 gallon tanks. I started with one to see how things might go. BTW, transporting these large tanks can be an adventure!
My soil is clay and I’m on the side of a hill in an old flood plain. I wisely built pads for each tank using crushed granite.
I have two down spouts that drain half of the back side of my house and both of them are routed into this first tank.
I started with a very simple gravity filter. Rain gutters collect loads of debris and this can easily clog tanks and lines. This gravity filter catches most of the “first wash” leaves and keep the tank relatively clean. Once the lower pipe fills up with the first water and debris, the remaining water will flow across the top into the tank. You must drain it regularly so it will work properly.
I know it’s going to overflow so this is a temporary overflow pipe and drain until I can build something better.
A specially-sized drill bit and screw tap allowed me to drill and mount a spigot on the end cap.
Which made it much easier to empty the gravity drain regularly.
This is my first effort to begin taking collected rain water and use it further down the hill in my garden. It’s more complex than actually needed because it allows for future expansion with more tanks via a balancing pipe.
This is my “old/original” square foot garden that uses the collected rain water.
I got tired of mowing around and moving the hose so I installed under ground piping to the garden.
It’s a fair way down there and has about 7′ of drop from the bottom of the tank so gravity will cause the rain water collected to flow from the tanks through the pipe and into the garden.
Outflow spigot at the garden and a continuing drain line just in case.
The single tank approach worked very well for 2 years and I decided it was time to expand the rain water collection tanks from 1 to 5. Again, transporting large 1000 gallon tanks is an adventure!
New rain water collection tanks positioned on gravel pads and ready to connect.
In the interim, my underground pipe developed a leak. I’m sort of a crappy plumber. Even with low pressure.
All 5 rainwater tanks will be connected via this pipe to balance their volumes. They will fill at different rates depending on their source and then because they are all connected from the bottom, they will auto-level across all 5 rainwater tanks.
All tanks are connected together with an individual spigot to drain and ball valve to isolate if needed.
The balancing pipe has a drain spigot at each end – just in case.
Each tank now has a dedicated inflow and gravity filter. Only that one dog though.
The tank on the East end had quite a reach!
Each inflow is connected to a rain gutter down spout.
I used old, left over deck planks to make boxes to protect the exposed piping. Damn dogs messing around under the deck.
I’m still only running a single overflow pipe though. This is going to be a problem when 4 4″ inflow pipes are running full blast into tanks that are full and trying to drain from a single 2″ overflow pipe.
We also make heavy use of rain water collection at our ranch. This is very helpful since we don’t have any wells on our property. This tank is 2500 gallons and you can see another small one of 250 gallons on the far right near the smaller building in the background.
After digging the trench for the balancing pipe (lower right), I just didn’t have it in me to dig another one. I also know there are more pipes buried there but not sure what they are for or where they are located. This was my best thinking for managing overflow from all of the tanks. It worked but turned out to be a big mistake for a number of reasons.
The new Hanging Overflow collects in the middle and drains out the back.
Here is one of those problems.
Up until now, I’ve only drained the front half of my house – not collected it. But, there’s another 100% additional water from the front half of the house!
I began using leaf filters at this time as well. I wish I’d known of them earlier. Do not attempt to collect rain water without these! I quickly had these leaf filters installed on all of my rain gutter down spouts.
That black plastic flexible tubing is wonderful for experimenting or temporary fixes but nothing beat good old PVC!
The new pipe from the front of the house is the lower one and it dumps straight into the overflow pipe. Living on the side of a hill presents some water management problems during heavy rains and draining the entire front half of the house around and down the hill is very valuable. Not long after this, I dug a duck pond at the bottom of the hill to collect this water.
Leaf Filters! Get you some!
I got real tired of busting my head on the Hanging Overflow and decided it was time to make a plan. This si the initial design.
And a detail plan for a big project that should have been done properly in the first place!
Lots more trench digging to get the overflow pipe underground. I did this by hand with a sharpshooter.
The West tank and front-of-house collector connected to the new underground overflow pipe.
Next tank connected to the underground overflow pipe.
The underground overflow pipe flows downhill from the middle and has a stand pipe for access if needed.
The underground overflow pipe dumps out at the back of the deck and is carried downhil to the duck pond in black plastic flexible pipes.
The East side of the front-of-house also uses black plastic flexible pipe to collect and send rainwater into the overflow pipe. It’s due for an upgrade to PVC soon.
I actually have 5 tanks and only 4 direct rainwater downspouts on the back of the house. The water from the front of the house drops too far downhill to collect in a tank so it’s sent into overflow. This 5th tank has no inflow and is only connected to the system through the balancing pipe. Storage but no collection.
The East side front-of-house flexible pipe is an experiment for collecting from rain water. This flows directly into the overflow pipe just like the West side.
And the West side front-of-house PVC pipe needed some supports – that water can get heavy!
I expanded and moved my square foot garden further downhill and just extended the pipe from the previous clean out on the original square foot garden. 1″ PVC pipe is more than sufficient for drip irrigation.
More trench digging! In this case, I’m making a 45 degree turn to avoid a bunch of trees and roots.
The new garden water line has a stub near the lower end that is even with the end of the overflow flexible pipe so that I can harden that in the future and add more water storage fed from either the overflow or by redirecting the garden water line.
The garden water line extension continues into the new garden and also provides water for the new orchard and vineyard.
I got tired of the dogs messing in my rain water stuff so I fenced under the deck with cattle panels. It worked great! Remember to leave a little gate too!
Time to replace the East side front-of-house black plastic pipe with buried PVC. This one has lots of turns and elevation changes over a short distance.
Tricky trenching around big rocks and downhill.
Check out all those crazy joints and turns!
I installed the brace on the leaning rock wall before attempting this project. It was still nerve wracking though! That rock area was probably one of the worst ideas I ever had and will be terribly difficult and expensive to undo!
Weaving the collection pipe through the fence and into the overflow pipe.
And getting it connected. Sometimes that black plastic flexible pipe can be really handy!
I finally got tired of mowing around 200′ of overflow black plastic flexible pipe and decided to replace it with PVC. My intention is that the PVC overflow pipe is solid enough to hold water so that it can drain into another set of tanks downhill.
That’s a LONG way!
A couple more joints and we’re back to ground level.
And a screen to keep out the critters. Water will flow from here on the ground to the duck pond further downhill. All rainwater from the front of the house and any overflow from the rainwater collected at the back of the house flows through this pipe.
I installed an overflow pipe on the stand pipe on my overflow pipe.
Meh, that fence can’t keep out all the creatures! Yeah, that’s a rattle snake.
Remember that handy little connection? – it leaks!
But a wrap or two of Rescue Tape on the inside solved the problem.
Comparing water height at the bottom of the new overflow pipe to the water in the tanks. The bottom of the tanks under the deck is 9′ above ground level at the bottom of the new overflow pipe. This will be plenty of height to add a couple 2500 gallon tanks down here and fill from the top.
The only way to know how much water is in the tanks is to knock on them and guess. This is my attempt to use a float rig to indicate water depth inside the tank. It didn’t work very well at all.
It should have worked and did with some fiddling but the friction of the line resting on two 90 degree turns was more than a fishing weight and half-filled clorox bottle could do well.
One part of my overflow piping was rough and ugly – needs work.
My very first concrete project!
Turned out nice. Most water flows through the pipe and any extra ground water can flow out the drain pipe above. Those cinder blocks are just setting there – not part of my project.
PVC pipe shavings can play hell with valves and quickly drain your tanks. I know this from experience. Check your timer vales frequently and watch your water levels!
I’ve had a couple leaks – all in my piping. It can happen in a flash. Now that my garden is substantially larger and I “depend” on rainwater, a leak can be catastrophic – especially during growing season. This approach proved to be OK in a pinch.
After the last leak that went undiagnosed for a week or so, I upgraded my water level gauge.
A standpipe at the end of the overflow line is the next step to collect and use more of the overflow water. Water will fill the underground pipe and rise to the top of the new standpipe before overflowing (again). The top of the standpipe will eventually connect directly to 2 more large tanks and fill them before overflowing.
In the mean time, Summer’s coming and the dogs need another place to cool off. The duck pond water can get real nasty and this stock tank dog pool should work just right.
The bottom of the overflow and standpipe was a bit tricky because it needs to be water tight but I also need a way to drain and clean. This is the very downhill end of my system and I *KNOW* that there is debris in it. It will need cleaning at some point and this approach allows me to do that.
Looks OK and the dogs like it! The pool fills from a spigot on the stand pipe and is connected to a float valve on the pool
And I can drain and clean it if needed!
Remember that leak I patched? Well, it failed again and that whole line started producing leaks. The trench was a bit crooked and my plumbing less than perfect so it was time to repipe. This is Luis. He dug that 200′ trench in less than a day.

I’m in the process of laying the new garden water pipe but it keeps raining and filling Luis’ trench with water. Following that fix, I’ll begin the process of adding two more 2500 gallon tanks at the end of the overflow pipe for additional storage. After that, who knows?