5 May 2010. Wednesday. Yesterday I had one of those AHA!! moments, solving the Mystery of the Water Flowing From the Closed Faucet. Let me tell you about it.
We have very basic indoor plumbing in our house here in Tanzania. In the bathroom there is a sink, toilet (western style, thank you very much), and a shower. Right next to the bathroom is the kitchen where there is a sink and one faucet with cold and hot water taps. That’s it. There once was a homemade solar hot water system, but that was broken long ago. Consequently, the house has no hot water (except only an instant hot water heater installed right on the shower head). There are hot water taps at each of the faucets, but when you turn them on you get nothing, not even cold water. The only taps that work are on the cold water side. That’s our situation.
A few weeks ago we noticed a very odd thing happening. When the shower was on in the bathroom, water flowed from the kitchen faucet even though the tap was closed tightly. Not just a drip, either, but a steady flow. It only happened when the shower was on, and no amount of tightening the kitchen tap would make it stop. I pondered that for days. I concluded it couldn’t be excessive pressure, because if anything, the water pressure on the kitchen faucet would decrease when the shower faucet released water. I even looked for an answer on the internet. I found lots about leaky faucets, but as far as I could tell, no one else ever had this problem of water flowing from a closed kitchen faucet only when the shower was turned on in the bathroom. I could think of no earthly explanation for water flowing from a closed tap, but I wasn’t ready to call it a miracle, either.
The extra water really wasn’t that big a deal. The only time it was an actual annoyance was when trying to do dishes while someone else was taking a shower. The extra water flowing into the dishpan did disrupt the chore a bit. That aside, the plumbing works fairly well, most of the time, and we are certainly grateful to have indoor plumbing. I chalked it all up as an unsolvable mystery and decided to live with it. But it still troubled me.
Then, just yesterday when the shower was running I decided to wash my hands, taking full advantage of the extra water flowing from the kitchen faucet. It was fun, not even having to turn the faucet on and off. As I stood there rubbing my hands and looking at the mystery water, a very intriguing question came to mind. Was the water coming from the side of the HOT water tap instead of the cold water side? I twisted off the hot water tap, and lo! The flow stopped. Once I discovered that, the solution instantly came to me.
This is a puzzler worthy of Car Talk, don’t you think? Send in your answers (to me, not Tom and Ray) on the back of a $20 bill! Be sure to enter often.
This is what was happening – the hot water taps in both the shower and the kitchen sink had been left in the open position. Normally that didn’t matter, because there was never any water pressure on the hot water side. But, with both taps in the open position and the shower turned on, the rising water column in the shower stem (which rose to the highest point of plumbing in the entire house) created enough pressure to push cold water backwards through the shower’s open hot water tap and further backward through the hot water pipes until it flowed out through the kitchen’s open hot water tap. When the shower was turned off, the water column drained out of the shower stem, lowering the water level to below that of the kitchen faucet, thus stopping the backward flow of water through the hot water pipes. Turning off either or both of the hot water taps prevents any backflow of water from the shower through the kitchen faucet.
Mystery solved. Problem fixed. Mind at peace.
