Dear Editor:
Greetings, fellow urban dwellers! As an intermittent 10 Cent Challenge [1] subscriber (I put in money when I have it, the Lord has seen fit to test our family lately) and semi-survivalist, I would like to talk about reverse osmosis (RO) filtration systems. Can you afford to depend on the municipal water system to provide clean water? In the event of water supply contamination, you can use portable systems such as the Katadyn or Big Berkey filters, but I want to save my bug-out supplies for bugging out. Also, the first indication that there is a problem is when people start getting sick, which means that you could already be exposed. A [daily use] RO system under the sink is cheap insurance at under $300, and you also save from not having to buy bottled water. When the municipal water system was contaminated, I was able to give drinking water to my neighbors. One [of them] has since purchased his own unit. These systems work on water pressure, so if your water is cut off, hen so is the RO system.
However, many times there is plenty of water available, just not clean water. For this eventuality, one can build a [RO] pressure chamber. I used a piece of 6″ PVC [2], capping it at both ends and standing it on end. On the top, install a half-inch valve and a Schrader valve (tire pressure valve), on the bottom end put a quarter-inch flexible tubing outlet. The assembly sits on a wire plant stand. To use this, turn off the water and disconnect the tubing inlet to the RO system, connect the pressure chamber tubing instead. Add water to the pressure chamber (I use a funnel with a coffee filter), then pressurize it with a bicycle pump, preferably one with a pressure gauge attached. RO systems work best at 40 psi [3], but provide water down to 20 psi. Add water and re-pressurize as needed, usually every 30 minutes or so depending on your chamber size. With RO systems you throw away a gallon or more of water for every gallon of water they make, so keep that in mind. Distillers produce cleaner water, but require a source of energy, which may not be available, so I consider them less reliable in troubled times. Keep a spare set of filters, replace them regularly, and prosper! – Justin B.