Letter Re: Bison Water Pump


I also have a Bison pump. It is installed right into my well along side the submersible pump.

My static water level is about 31 feet. My pump is about 15 ft from my house (a pressure system). I am not very savvy on this stuff, so maybe you can EDUCATE ME. How are you getting your bison to pump in your water? I doubt your well is in your basement.

HJL Responds: Unfortunately, you will probably not be able to reproduce the results of those readers who have their pumps mounted indoors. Very few people have their wells inside their houses (though I have seen a few), because servicing the well thus located is very difficult. These readers are using the existing plumbing from their submersible pump, and when activated, the Bison pump draws water through the original submersible pump up through the standing pipe and into the house plumbing. As yesterday’s reader noted, the pump is not designed to contain pressurized water all the time, so his pump is isolated with a valve when the submersible pump is working. When electricity is no longer available, the valve he has at the bottom of the pump is opened to allow the Bison to pull water through the plumbing. He also has to have an isolation valve to shut off the water supply to the rest of the house so that the Bison pump does not draw from the house, creating a vacuum in those lines.

The whole reason this works is because the standing water line in their pumps is fairly shallow. Here is some simple math: 1 cubic inch of water weighs ~0.036 pounds. Multiply that by 12, and you find that a column of water one foot high exerts ~0.433 pounds of force. Remember that you are not actually sucking the water up the pipe; you are creating a vacuum, and the air pressure is pushing the water up the pipe. At sea level, the air above you exerts ~14.5 pounds of force, so 14.5 divided by 0.433 equals 33.49 feet. If you create a perfect vacuum in your pipe at sea level, the air around you will push water up the pipe a maximum of 33.5 feet. Now realize that most of us live at higher elevations and that there is some friction loss in the pipe itself, and it shrinks that number. In addition, you are not interested in just pushing the water up the pipe. You want to use the water, so you can’t push it to its absolute maximum. You have to push it less to get it to flow. The recognized working average is about 24 ft. If you water table is less than 24 ft lower than your Bison pump, you can draw water through it like the reader yesterday did. The higher the water table, the more water you can draft this way (higher flow). If your water table is more than about 24ft lower than where your pump is located, you will not be able to use this method.

In my case, the static water level is at 100ft, so I have to have a system mounted on the well head that puts the pump down below the water level (about 150ft in my case) and has a shaft inside the pipe so the lever at the well head can work the pump 150 ft below.