This truly revolutionary pump could be your ticket to a completely independent water system that is not reliant on electricity or fuel. A ram pump uses the pressure of gravity on water to pump the water uphill. It generally needs a water source with at least 5 feet (+-) of head (fall) and a minimum of 3-5 gallons per minute of flow in order to function properly. The more head or flow that you have, the faster it pumps the water. Most of the water is wasted in the pumping process, so only a small percentage actually makes it up to the cistern.
Gathering the Data You Need
In order to determine if a ram pump will work with your particular situation, you will need the following information to use in a formula:
- Flow of water source (in gallons per minute). There are a number of methods to determine this. If it is a small enough amount of water, the stream can be diverted into a 5 gallon bucket. Just count the number of times the bucket fills up in one minute, multiply that times 5, and you have the approximate number of gallons per minute (GPM) that your water source yields. For larger water sources, use the "Weir" method described on the Rife Ram Pumps web site. www.riferam.com . The amount of flow used in the formula will also depend on how much flow the ram pump model you choose can handle.
- Vertical fall or head (in feet) from the drive pipe intake to the ram pump itself (see picture). For more info, see: How to Measure Vertical Fall of Your Water Source
- Elevation rise (in feet) from the ram pump to your cistern. For more info, see: How to Measure Vertical Fall of Your Water Source.
Once this information is obtained, apply it to this formula:
V x F/E x 0.6 = D
V = available flow of water in gallons per minute(example - creek flow is 50 GPM but the ram pump you choose can only handle 10 GPM. You would use 10 GPM in the formula).
F = Vertical Fall from intake on drive pipe to ram pump (in feet)
E = Elevation rise from ram pump to cistern (in feet)
D = Delivery to cistern in gallons per minute (for gallons per hour, multiply "D" times 60; for gallons per day, multiply "D" times 1,440)
In other words: The amount of available water times the vertical fall to the ram pump. This result is divided by the elevation rise to the cistern. All this is then multiplied times 0.6 (the normal efficiency of a Rife ram pump. This yields how many gallons per minute you can expect to be pumped to your cistern every minute.
Choosing the Correct Model of Ram Pump
After finding which models of ram pumps will fulfill your requirements for "vertical fall" and "elevation rise" (see above) start out by using the specifications of the smallest model that can handle the flow from your water source. If you find that it pumps far more water than you need, keep backing down to the next smaller ram pump until you find the one that can pump the amount of water you need with a comfortable safety margin.
There is a video available from Lehman's that demonstrates ram pumps in action ($10). Also, if you have difficulty in figuring out whether or not a ram will work for you, contact Rife Ram Pumps for help and more information. Be sure to give them the following information about your particular situation:
- The flow of the water at the source of supply [intake for drive pipe] (in GPM)
- The vertical fall from the source of supply [intake for drive pipe] to the planned location of the ram pump (in feet).
- The elevation gain from the planned ram pump site to the planned location of the cistern (in feet)
- The distance between the source of supply [intake for drive pipe] and the ram pump location (in feet).
- The number of gallons required per day.
Home Made and Creative Options
Home made options abound and can be a great solution for budget minded folks. But if you have the money, it is hard to beat the time-tested cast iron Rife Ram. I have heard of these units being used continuously for 50 years or more with only routine maintenance like changing o-rings. Phenomenal!
It is only recommended that a ram pump deliver water to an unpressurized cistern uphill from the point of use and then let gravity do the work of pressurizing the water system. However, I have heard of some who have managed to get a somewhat workable system when no hill is near by simply connecting the output of the ram pump to their pressurized household water system. This is not recommended and your results may vary depending on the amount of water available, the amount of head to the pump, and the amount of vertical rise from the pump to the house. Most likely the volume of water would be quite low and it remains to be seen how the ram pump and your plumbing would hold up under this kind of use, but I would be remiss for not at least mentioning what some creative folks are doing.