Well with Cistern?

[Smb2415]

Existing 1700sqft 3bd/2bath home has a 115' 6" well with a 1/2hp submersible pump. Town records show well yield at 10gpm. Plumbing from well (not sure of drop pipe yet) to pressure tank in home is 1-1/4". Piping is about 50' and level run. Pressure tank was just replaced due to age related failure and upgraded to 120g. 1" hot and cold mains run from the pressure tank through the rest of the house. Home currently occupied by a family of 3. Currently system works ok though pressure and volume were previously issues with the smaller pressure tank. Since adding the new pressure tank at 50/70 psi and increasing the size it has helped.

Due to some family matters an addition with an in-law apt will be added on. This will add another 3 people and 2 bedrooms and 2 baths bringing the home to a 6 people and 5 bedroom/4 bath home. The septic system will also need to be addressed though thats a separate topic. With that in mind I figure the water system design needs to allow for 12-18gpm. GPM is estimated ooff the total fixture count, simultaneous use, and desired PSI/flow to achieve as close to city water as possible.

With the the well yield being at 10gpm Im thinking an underground cistern will need to be added to the system so that proper volume is available. ?maybe 1200g tank (6 people x 100g/day x 2days)? Because of the increased volume pressure upgrades to the filtration (sediment, neutralizer, softener, UV) after the well pump are also planned off of a 1-1/4" manifold to accommodate 12-18gpm.

what I dont fully understand is around how to select and install the right submersible pump in/to the cistern. From what I read I think I want the pump in the cistern and for it to be installed in a vertical manner.
- are there any links where I can learn more about this type of setup?
- How does that work without a well casing?
- How do you keep it firmly in place and ensure that it has it being properly cooled when water in the tank runs low?
- What controls to I need to leverage my existing well pump and pressure switch while adding the cistern submersible?
- Float switches, I know I need them, type, how high/low?
- what type of connection is needed to the cistern? Read something about a flexible connector?
- is there some type of drain required by code for the underground cistern? how does that work?
- any other considerations for the cistern/well?

Something similar to this is what Im thinking.

https://terrylove.com/forums/index.php?attachments/well-feeding-cistern-with-sub-booster-jpg.94429/

 

[Reach4]

I am not a pro. I think 10 gpm from the well is sufficient for both units. An unpressurized cistern is extra potential trouble or contamination. Now if the prime reason for the cistern is part of a water treatment system, that would be different.

 

[Sponsor]

 

[Bannerman]

Agree'd, with 10 GPM directly from the well, a cistern should not be required.

pressure and volume were previously issues with the smaller pressure tank. Since adding the new pressure tank at 50/70 psi and increasing the size it has helped

Water is supplied by the pump directly from the well, not from the pressure tank (PT).

Pump's are designed to run constantly. It is repeated cycling ON>OFF that causes the pump, check valve, pressure tank & pressure switch to fail prematurely.

The pressure tank's main purpose is to act as a timer, to ensure the pump will operate for a minimum amount of time once activated, thereby reducing cycling. The minimum run time is usually 60 seconds after water flow has stopped, but 120-seconds is preferable. Your 120 gallon tank will store approx 30-gallons water, so your pump will become activated when ~30-gallons has exited the tank, and will be shut off whenever ~30 gallons has re-entered the tank.

The pressure tank also causes the plumbing system to remain pressurized while the pump is shut off so water will continue to flow to faucets/appliances without waiting for the pump to be activated.

What was the previous system pressure range setting? I anticipate it was much lower, so increasing the pressure switch's pressure range setting will be the cause for increased flow and pressure to the home's fixtures, not the larger PT.

As an upgrade to your current well system, consider adding a Cycle Stop Valve. A CSV will not only prevent the current pump from cycling anytime more than 1 GPM is flowing to fixtures or an appliance, but a CSV will also result in constant pressure to fixtures whenever the pump is operating.

Although a CSV eliminates the need for a large pressure tank, since you have already equipped your system with a new 120-gallon tank and likely a new pressure switch, only an actual CSV would be needed. With the current 50/70 psi pressure switch setting, the system could then deliver ~65 psi constant once the pump is running. If your pump will support 60/80 psi, then the CSV could be calibrated to provide ~70 psi constant.

For info regarding the function and benefits of a CSV, see the interactive animation at the link below.

CSV Interactive Animation

 

[Smb2415]

Agree'd, with 10 GPM directly from the well, a cistern should not be required.



Water is supplied by the pump directly from the well, not from the pressure tank (PT).

Pump's are designed to run constantly. It is repeated cycling ON>OFF that causes the pump, check valve, pressure tank & pressure switch to fail prematurely.

The pressure tank's main purpose is to act as a timer, to ensure the pump will operate for a minimum amount of time once activated, thereby reducing cycling. The minimum run time is usually 60 seconds after water flow has stopped, but 120-seconds is preferable. Your 120 gallon tank will store approx 30-gallons water, so your pump will become activated when ~30-gallons has exited the tank, and will be shut off whenever ~30 gallons has re-entered the tank.

The pressure tank also causes the plumbing system to remain pressurized while the pump is shut off so water will continue to flow to faucets/appliances without waiting for the pump to be activated.

What was the previous system pressure range setting? I anticipate it was much lower, so increasing the pressure switch's pressure range setting will be the cause for increased flow and pressure to the home's fixtures, not the larger PT.

As an upgrade to your current well system, consider adding a Cycle Stop Valve. A CSV will not only prevent the current pump from cycling anytime more than 1 GPM is flowing to fixtures or an appliance, but a CSV will also result in constant pressure to fixtures whenever the pump is operating.

Although a CSV eliminates the need for a large pressure tank, since you have already equipped your system with a new 120-gallon tank and likely a new pressure switch, only an actual CSV would be needed. With the current 50/70 psi pressure switch setting, the system could then deliver ~65 psi constant once the pump is running. If your pump will support 60/80 psi, then the CSV could be calibrated to provide ~70 psi constant.

For info regarding the function and benefits of a CSV, see the interactive animation at the link below.

CSV Interactive Animation

previous pressure tank was setup and verified as 40/60psi.

My concern with the 10gpm well flow rate is when multiple fixtures are in use I won't be able to meet the demand. Also, once the water in the casing column is used and the demand persists then I risk pump running dry and likely also increasing sand/silt levels as the well veins adjust. My experience in the 10yrs with this well so far is that it works well for the 1000sqft house it was years ago though the house and demands grew to 1700sqft and now planned for likely another 800-1000.. not that soft master but people/fixtures do. Not sure how this will meet the demand with or without a CSV. Volume is volume, no? If not a larger well pump or cistern then what would you recommend?

 

[Valveman]

Rarely if ever are all the taps open at the same time. I use 5 GPM as a rule of thumb for enough to supply a normal 3X2 house. 10 GPM is enough to supply two houses. A 10 GPM pump will actually produce 12-14 GPM if needed, the pressure just decrease a bit if the flow gets that high. However, I find the average flow rate for a set up like that to only be about 3-5 GPM. The problem is not usually that the pump does not make enough flow, but rather it makes more GPM than is being used, which is what causes the pump to cycle on and off. I think the pump you have when controlled by a PK1A with a 10 gallon size tank, will supply plenty of flow and strong constant pressure to both dwellings.

 

[Valveman]

If later you decide a storage tank is needed, the well pump can be used to fill the cistern as well as supply water directly to the houses when needed. This gives you a back up pump in case one fails during a holiday or something. If the cistern pump fails you can get water directly from the well. If the well pump fails you have what water is in the cistern to live on while the well pump is being serviced.