Can you add a larger pressure tank after filter?

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Hello all,

I am having problems with the water pressure in my house and am getting even more pressure from my wife to fix it. This is my first home with a well system and i dont have too much knowledge on plumbing and well systems. Your expert help would be greatly appreciated.

When I turn on a shower head or faucet in one room the kitchen faucet or shower in other rooms barely provides water. if any tap is on in one room the other room will not have pressure. I believe the problem is the size of the current pressure tank which is about 4.5 gallons.

The current system is setup so that the small pressure tank is first from the well then it goes into a spindown filter and then into a 3 stage filter then into a UV system and then into the water heater and rest of the house.

The solution I thought of in my mind is to add a second larger 32-gallon pressure tank after the UV system and 3-stage filter but right before the line splits off to the water heater tank and the rest of the house. Is this a solution to my water pressure problem? IS there a problem with adding a larger tank after a smaller tank?

Thank you


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Where is the pump-- down the well (submersible)? If yes, you can probably turn up the pressure... but first check where the pressure is being lost.

With a 4.5 gallon tank, and you are not cycling a lot, you probably have a CSV.

A bigger pressure tank will not help with your weak shower/faucet water flow.

What does the pressure gauge at the pressure switch say? Put a garden hose thread pressure gauge after your filtration. That could be at a laundry tap or the drain valve on the WH. If you are losing 10 psi thru your filters, you want to figure out which filter is causing the big loss.

How often do you change the three filter cartridges?


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Ontario, Canada
into a spindown filter and then into a 3 stage filter then into a UV system and then into the water heater and rest of the house.
Bypass the 3-stage filter to determine the amount of flow restriction that is resulting from those filters.

Once the well pump has been activated, water pressure is provided by the well pump, not the pressure tank. A 4.5 gallon pressure tank, will result in ~1 gallon water delivery before the pump becomes activated. If a CSV is not utilized with such a small tank, then I expect your well pump will be cycling far too often which will severely reduce the lifespan of the pump, pressure tank, pressure switch, check valve etc.

Without a CSV, a larger pressure tank will reduce but will not eliminate the pump cycling. The correct location for a larger or an additional pressure tank will be where the 4.5 is located, or directly beside it.

I suspect the 3-stage filter is causing a significant flow restriction so locating any pressure tank after the flow restriction, will most likely result in a greater amount of cycling since the restriction will slow down flow to the downstream pressure tank. Since the pressure switch will continue to be located where the 4.5 gallon tank is located, the pressure switch will continue to shut off the pump when the 4.5 gallon PT becomes full, but water will then continue to flow from the 4.5 gallon tank while there is slower flow through the restriction to the larger tank. I anticipate this will likely cause the well pump to cycle multiple times before the larger tank is finally filled. Any water use after this will be initially flowing from the larger tank, with the flow restriction preventing the 4.5 gallon tank from loosing pressure at the same rate as the larger tank, which will probably delay when the pump will become activated.


- If your system is not presently equipped with a CSV, install a CSV to provide constant pressure and prevent cycling even while utilizing only the existing 4.5 gallon pressure tank.

- If the 3-stage filter unit is proven to be the source of flow restriction, either eliminate that unit or replace it with a larger, less restrictive system.

Perhaps your current 3-cartridge configuration utilizes a coarse sediment filter (10 micron or greater?) followed by a finer sediment filter (1-2 micron?) and maybe a carbon filter?. If so, maybe elimnating the highest restricting cartridges such as a 1-2 micron and a carbon cartridge will reduce the restriction to an acceptable level?

The recommended effective flow rate for carbon media is 1-3 GPM per cubic foot of Granular Activated Carbon media. Carbon cartridges often utilize carbon block media which is too restrictive, and a 10" carbon cartridge contains too little carbon media to provide much benefit for a point-of-entry application.
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