Water System and Cistern Questions

[MikeInKS]

First off, I just want to call out that I've found this an incredibly useful forum and really wanted to take a moment to thank everyone here for that. Now that I've buttered everyone up, hopefully you can forgive the very long post.

I have a 6" diameter low yield well - ~2 GPM specifically - at ~300 feet in hard rock. Pretty disappointing all around but I'm going to make it work with as minimal a lifestyle shift as possible. The bore holds maybe 100-150 gallons of water all told.

Since I have a few acres and do actually expect to have a bit of a yard as well as a normal family of 3 water-usage lifestyle, I know I'm going to need a cistern. I have a convenient location in the basement where I can get up to about 2000 gallons stored before it starts becoming a bit of a hassle. This would be a homemade water tank ~11' x 3' x 8' and using a potable water liner - something like these. I'd build the tank out of steel framing and plywood attached to the concrete with steel studs epoxied into place.

My plan is for the well pump to be hooked up to a float valve in the cistern to try and keep it topped off at all times. I was looking at these specifically. The well pump would run through a Pump Saver Plus or such to protect from running dry. The water from the well runs through some spindown sediment filters until it gets to the cistern itself. I don't really have a sediment issue but this is very cheap insurance if you look at these things over the long haul.

In the cistern would be a second pump. I was thinking a submersible with cooling shroud. This in turn would be hooked through another float switch to prevent running when the water is too low in the cistern. This would run to a typical cycle stop valve setup with the exception being a larger pressure tank (20 gallon Welltrol) just to avoid turning on the pump for simple toilet flushing and hand washing. From there, the water is broken up a couple ways: toilet tanks and such get direct water, no more filtering. Anything else runs through the appropriate filters until it goes to the destination. I'm not sure if I need to do any filtering at all as we are still developing the well but I don't want to be a position where I cant.

So now the questions:

1) Ideally the well pump would run from full well to empty in one shot, not cycling at all. This could be done with a simple "time since last ran" calculation combined with a "once running, stay running for X amount of time". I'd still want a catch all "run dry" protector in there as well but is there a product that does this? It seems a lot cleaner for a cistern system like mine?

2) What is a good choice for the in-cistern pump. It seems a straight up submersible well pump with a cooling shroud would be a solid choice? But what GPM is needed for a typical house? Sizing this has proven a lot more fuzzy than I expected.

3) In practice, what size should the cistern actually be? In theory, the well can put out 2880 gallons a day but Id never count on it. It feels like making a tank larger than can be refilled in a single day (even with abnormally heavy usage) is a bad idea but I can't say why. Sadly, as this is a new property and new house, I really have no baseline for water usage other than a small family of three and we are not terribly wasteful.

4) Is it better to use a float valve and a pressure switch than a float switch for the well pump? Long term reliability is a key concern of mine and if this approach is more reliable over time than I'm all for it.

Thanks in advance for any help!

-Mike

 

[Craigpump]

Brand new house? What are the state regulations for the well diameter, depth and yield?

The average usage is about 80 gallons per per person, 3 people =240 gallons. 2 gpm works out to 2840 gallons per day.

I think you'd be FAR better off spending your money on getting the well yield up. Hydrofrac it or drill it deeper

 

[Sponsor]

 

[MikeInKS]

Brand new house? What are the state regulations for the well diameter, depth and yield?

yes, it's a new house. As for the state regs, I can't recall them but I believe we meet them with the bore hole storage already. It's very borderline though and only works based on the number of people in the house.

I think you'd be FAR better off spending your money on getting the well yield up. Hydrofrac it or drill it deeper

My understanding is that hydrofracing has an average increase of 50% which would only be 3gpm and still require just as much of a cistern. Of course we could get lucky and hit the lottery and have 20gpm from fracing but that could have happened when we drilled as well and clearly didn't.

As for depth, I'm in an area where water quality drops fast with depth. Both salinity and the chance of hitting oil increase substantially. My understanding is that at 320 feet, I'm already pushing it for water quality without expensive treatment. One other thing - we hit that 2gpm as high as 180 feet or so - all that extra depth didn't seem to increase it at all so I'm nervous to gamble and just keep throwing money into a hole. Is there any way to tell at all if my well is a good candidate for fracing?

 

[Reach4]

2) What is a good choice for the in-cistern pump. It seems a straight up submersible well pump with a cooling shroud would be a solid choice? But what GPM is needed for a typical house? Sizing this has proven a lot more fuzzy than I expected.

That pump in the shroud / flow inducer can be tilted as much as 90 degrees to let it pump lower.
Flow inducer sleeve:
Four inch solvent weld D2729 sewer pipe is a good size. OD 4.215 ID 4.056
So is Schedule 40: OD 4.500 ID 4.026


7 GPM is enough for many houses, but since you are going to be using a 1/2 HP submersible probably, the pump you want would probably be 10 GPM in the tank. That would probably give you about 13 GPM. Look at the pump curves or the easier-to-read tables.

You want a float switch control tank filling. I would use a 1/2 HP 5 GPM pump. It still delivers water from 320 feet, although the flow might be down to around 3 GPM... Your pump is probably around 280 feet, and that pump would give about 4.5 GPM at that depth. When the water is 200 ft down, expect about 5.8 GPM.

 

[Craigpump]

Here in CT we don't have the same water quality obstacles you do, in most places we can drill to 1300' and not encounter salt water. There is no oil or gas production here.

We like to see wells that have 300' of borehole to work with, but there have been times when we've been very successful at shallower depths. Very successful meaning 5+ gpm. I don't know where you got the info that hydrofracing increases well yield by 50%, some of the best results are from wells that have very low initial yields. If you hydrofraced your well and increased the yield by, say 50% and brought the static level up to within 30' of surface, you'd have close to 400 gallons standing capacity followed up by a 3 gpm yield. I would consider that more than adequate for domestic purposes.

While you can store a lot of water in a cistern, you have to
1) be able to fill it
2) prevent it from becoming contaminated or install a UV light
3) it requires another mechanical system to service & mantain
4) when you sell the property, a lot of people will be very hesitant
5) cisterns & tanks require piping & controls that and on occasion do fail and flood basements

The best tanks are called wells.

 

[Valveman]

I agree anytime you can make do without a cistern you are saving yourself a lot of headaches. But when a cistern is needed, it is needed. You can also set it up to use both, straight from the water well, and from the cistern. Switching a couple of valves would let you get water directly from the well if/when the cistern pump is out for service or something. This way you use a pressure switch for the well pump and the float switch in the cistern tank opens when the float switch is low. This can be done with a jet or a submersible to pump from the cistern.