The community where we live has Municipal Utility Districts (MUD) that sell rent “provide” us our water.  Normally everything works out well and the water is clean and the lawn is green but now the MUD is getting lazy and wants everyone to cut their water consumption (mainly stop watering their lawns everyday) because ‘apparently’ our water usage as a community is out of control.  Ok fair enough, saving some water probably isn’t a bad idea especially considering that I would turn my sprinkler on several times a day just to mess with people.  But unlike a sane person, I cannot control my desire to horde a little bit of water on the side for no real reason (we can still water every other day and soaker hoses are still allowed everyday).  I am not at ‘prepper’ level yet, but I am sure my neighbors had a solid WTF moment when I rolled three 55 gallon barrels out of the back of the Jeep.

I found the barrels on Craigslist for $10 a piece and I was pretty pleased with the toxicity level of what they previously stored.  The remnant material is supposedly biodegradable and has a nice citrus smell.  I wouldn’t eat anything that was watered with this barrel but hey who doesn’t want their lawn to smell citrusy fresh.

So after rinsing out the barrel to make it ‘clean’, I sprayed on some toxic spray paint to make it blend in with the back of the house a little better.  For my first experiment, I am only using one of the barrels.

After a little research on the internet, I discovered that there are actually a lot of people doing this right and doing great things (like feeding their families) by collecting and storing runoff water.  I want to apologize now for letting those people down.  I did learn though my research that the key in the collection business is to increase the surface area from which you are collecting.  The easiest way to do that is to hook up to existing structures that already channel water – your rain gutters – simple enough.  The math is kind of crazy, but a 1000 sqft roof can collect something 600 gallons after a 1 inch rain.  All I want is 55 – for now.

Rain Water Collection SetupSo without further preparation, I headed to the garage to find any random part that might help.  I drilled a hole at the bottom of the barrel and stuck in a threaded sprinkler head ‘extender’ and sealed it with some probably toxic shower/bath silicon.  From there I headed to Lowes for some pieces to connect to the gutter and a 1/2 inch shut off valve for my protruding sprinkler tube.  In retrospect, I should have hit Lowes first and purchased a screw on valve but I was impatient.  I will probably end up doing that when the 5′ inch pipe breaks off.

I wanted to test it out but in Texas, rain doesn’t happen a lot (hence the watering the lawn too much problem).  So I decided that, in the name of science, I will spray down the roof and see how much water I can collect.  I immediately learned that it was time to clean the gutters.  Since there is no rain forecasted for the next 10 days, what is the rush on cleaning the gutters.  I unscrewed the second port of the barrel and filled it directly with water.  To my surprise, no leaking.  Woohoo, now it is time to get technical.

About a month ago, I purchased a 1/2 inch water flow sensor and I figured this was a perfect time to test it out with an Arduino and an Arduino Ethernet shield that has an microSD slot for data logging.  The software examples provided for the water sensor by Adafruit and the datalogger by Arduino made the setup easy.  The SD cards used pin 4 and the SPI pins (it also requires pin 10 to be set to out) and the sensor can sit on any other pin (I kept it at pin 2).  I put my combined slightly modified code (I wanted to see gallons since thinking in liters is a mental road block – thanks US teachers) on gitHub. The code basically counts the rate that the little wheel spins inside the sensor and determines the flow rate in liters.  Then I convert that to gallons and write both to datalog.txt on the microSD card.  For testing, I shoved it in a Crystal light tube to give light water proofing.  Long term I could use this data to have a relay open and close a solenoid valve based on how much water I want to let out.

Arduino + Arduino Data Log Shield with H2O Sensor

My results from the sensor – with the barrel half full, I was dumping out about 2.2 gallons of water per minute with the valve open.

I am a little worried about growth of algae and most importantly our friends with west-nile the mosquitoes.  The plan is to try some of these non-toxic “Mosquito Dunks“.

There are several commercial solutions that look a lot better but cost about $100 for the barrel and valve.



  1. edwin -

    nice setup. With regard to our friends the musquitoes, the Musquito dunks last 30 days so that is a continuing cost and worry. In some 30 world countries i have seen them use a layer of floatable material that prevents the musquitoes from reaching the water to lay their eggs. Often this is the uniquitous white foam packaging pellets. Not sure what the toxicity level of that is, but you could think of other stuff: pumice, or just a sheet of plastic slightly bigger than the water surface floating on it.

  2. edwin -

    Even simpler: how about a bugscreen in yr barrel? The rainwater will easily go through but musquitoes wont

    • Thomas -

      I got an email from someone stating that they put fish in the barrel to eat the mosquito larvae. Not sure how well that would work with the heat in Texas. I am assuming they screened the output and make sure the water cannot drop below some number of gallons.


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