I have a 3000 gallon water storage tank that my 4 inch well pump (800 feet down) fills up and the water tank then gravity feeds about 5 feet into a shallow well pump that pumps water into a 60 gallon pressure pump about one foot away. The pressure pump sends water to the house about 300 feet through one-inch pvc pipe into the house. The shallow well pump and pressure tank are located inside my pump house. The water pressure inside the house is OK but I would like it to be much higher than it is. Can I cut into my one-inch water line right before it goes into the house and install a second pressure tank and then connect the out pipe to the water line going into the house and if so, will it raise the water pressure substantially so that the showers have more pressure and etc. or would I have to install another shallow well pump before the second pressure tank or am I wasting time and money on all of the above. I can live with it the way it is but it would be nice to have greater water pressure coming out of my spigots and shower heads. Thanks for any advice.
Water – have two pressure tanks on the system
waterwater-pressure
Related Solutions
Two factors matter: flow rate and pressure. Pressure is determined by friction loss and elevation adjustment. Since the tank and house are at the same elevation, we don't need to account for that. We do need to account for your friction loss, though. To do that, we need to know what your pipe diameter, length, and flow rate.
We start with flow rate because the amount of water flowing through a pipe determines its friction loss. That's what we size the pipe from. Your flow rate should be based on maximum flow: everything that could possibly ever run at one time. Your shower, dishwasher, washing machine, somebody washing their hands, etc. There's no uniform minimum standard for that, so check the fixtures around your building to find out how muh they would draw.
According to a plumbing design guide from Michigan, this can vary from 7 gpm for one bathroom to 17 gpm for a 3-4 bathroom residence. After you've determined the flow rate, you must select a desired pressure for the house inlet pressure.
If your pump is able to fully supply your house without the aid of a tank (sufficient flow at operating pressure), then your only consideration for tank size is the cycle time of the pump. For smaller pumps, you want your tank to provide at least 2 minutes of water. For larger pumps, you may desire a higher cycle time. There is no harm in a larger tank size.
If your pump isn't able to provide that level service, then you'll need to size your tank to provide supply for a period of time. Remember that pump supply in gpm is also related to pressure. The more pressure the pump needs to provide, the less flow it will have. Calculate your pump flow based on the pressure needed to charge the tanks.
The ultimate calculation is (maximum flow * maximum minutes) > (tank capacity / minutes + pump capacity * minutes). You can use any combination of tank and pump capacity as long as the tank + pump capacity meets your demand needs. A 1 gpm pump and a pressure tank that can supply 300 gallons could probably hold you over just as well as a 14 gpm pump and 28 gallons of supply tank. Remember again that supply is not equal to full capacity: you only have supply if it is higher than your necessary pressure. Your goal is to find a combination that is most cost effective.
For another good resource related to tanks, see Flotec's pre-charged pressure tank FAQs.
By the way, since you gain 1 psi for every 2.31 feet of elevation gain (referred to for some reason as "feet of head"), you can get a lot of "free" tank supply pressure by putting your tank at a higher elevation, though that will increase your pump charging pressure.
For absolute luxury, keep your entire supply system able to supply above your desired household pressure and slap a pressure reducing valve on the supply line just before it reaches the first appliances. 60 psi is the ideal dream coming out of your pressure valve (fantastic showers!), but pressure does cost in terms of electric usage for lower pump capacity because, again, higher pressure means lower flow. Most systems are designed to start charging at 40, 30, or 20 psi, though. Note how the pressure corresponds to the amount of water that can be supplied in this example tank.
You have the idea of it, I think, so long as you're not going for something cockamaimie like tying the air charge sides together. I don't actually think you are saying that; in any case, don't do that.
You just set those both 2 psi below the cut-in (ie, 18 PSI for a 20/40, 28 PSI for a 30/50 38 PSI for a 40/60 pressure switch setting, with the water side empty) and connect the water line to both tanks.
If the old vertical tank is still in usable condition, you could tap it in as well, though logic would call for a 1/4 turn ball valve; that might be a good idea for the new tank as well, since eventually it will be old, and may need service/replacement - price of the valve .vs. being able to service/replace the tank without shutting the whole system down - your call.
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Best Answer
That sounds like an overly complicated setup with far more pumps than it should need. Or else you said pump when you meant tank in two places, actually, re-reading it.
In short, you can have as many pressure tanks as you like. Locating them closer to the point of use (the house) would be helpful, to a limited extent. That limited extent is the "effective volume" of the pressure tank at the house - while it's got pressure, you get better pressure at the house. As soon as it runs out of water and you become dependent on the pump, the pressure loss of the 300 feet of 1" PVC to the house comes into play, until you slow down your water use to the point where the pressure tank at the house fills up again.
If you do not change the setpoint pressure, the peak water pressure in the house will not be affected at all. Once the pressure tank at the house is depleted, the pressure will be the same as it is now. If you have a pressure gauge at the house now (or can add one) it might be useful to know the pressure at the house when "loads of interest" (showers, say) are drawing water.
Most pump controls can be altered to have a higher setpoint pressure, and most well pumps will provide that, within reason. General recommendations are to stay below 80 PSI - but if you are now running your pump on at 20 off at 40 (a typical default) you could turn it up to on at 30 off at 50, or on at 40 off at 60 - you will need to adjust your pressure tank (and any you may choose to add) for the higher pressure, particularly if they are bladder-type tanks - with the system drained, a bladder tank should typically be 2 PSI less than the low water pressure setpoint (ie, 18, 28, or 38 for the three ranges I've just given) and you may need additional pressure tank volume (because the effective volume of water a pressure tank can hold goes down as the system pressure goes up.) So, you can probably get more pressure without another pump, and possibly without another tank, but we'd need more details of what your system is doing now to know that for certain.
Unless your water use is extreme, 300 feet of 1" PVC pipe should not have a lot of effect on the pressure - at 5 gallons per minute, about 2.2 PSI - at 10GPM, 8.2PSI, 15 GPM, 17.4 psi