Help on new install, low yield well (sanity check)

[tenflyer]

Good morning, never had a well before but we are about to make that transition and this forum has been AMAZING for me to learn. I don't have my final well report yet it was just drilled last week but indications are it is low yield at about 1 GPM unfortunately. The well is about 500 ft, and 8" wide so there will be a decent storage in the bore (don't have the static level yet or depth the pump will be to know that exact #). We want to scale our system properly for 5 bedrooms and 4.5 baths, 3 levels including the basement. Allow for some lawn irrigation, and also I'm going to have a fairly high end shower with multiple body sprays on the top floor, the digital valve on my shower alone can support up to 17 GPM at 45psi (though normally the shower will probably use closer to 10). So I'm guessing peak would require 20 GPM.

So bottom line is I know I'm going to need a storage tank in the basement, probably in the 500-1000 gallon range. I think it is easy enough to make sure that gets supplied properly from the well since the well should in theory yield 1,400 gallons a day.

So based on what I'm reading here I'm going to ask for the the attached setup that valveman has posted several times. My question is on the booster after the storage tank. If I require say up to 20gpm at a constant pressure of 50 psi, I'm trying to calculate the size booster. Most supply lines to the fixtures will be 1/2" but my shower valve requires 3/4". I'm trying to get the builder to do PEX not CPVC I'm reading up on the friction loss between the two.

So if I'm following the calculators I can find online, if I stick with Grundfos I end up needing something like the CMBE 5-62 which is a pretty expensive/jacked up pump.

Am I on the right track with this? I want to make sure I get this right, even if oversizing a bit and I don't mind spending the extra $$?

 

[Craigpump]

My personal opinion is that static storage in a basement is a horrible idea. Tanks sweat, they require another pump and tank and worst of all is the potential for leakage due to failed piping and/or controls that malfunction. Did I mention they are expensive?

Instead, do what you can to maximize the tank you just drilled in your yard, it won't sweat, you only have one pump and tank, and it won't leak..

 

[Sponsor]

 

[tenflyer]

Can I get that kind of flow and pressure from 4oo-500 or more feet though? Initiall when I looked at some of the performance charts the GPM really takes a hit at that dept. But I'll start researching that angle more, I do understand what you are saying it takes out some of the potential problems.

 

[Craigpump]

You REALLY have to know the static level, total depth and yield to design a pump system.

 

[tenflyer]

Understood I'll post those numbers when I get them hopefully next week to get your input.

 

[tenflyer]

Ok Craigpump (or anyone) here are my well report stats finally: 8" wide well, 520' deep. static water level 54'. Yield test shows unfortunately only 1 gpm so just at the acceptable # for the state. Will be building a 5 bedroom 4.5 bath house. Other than the well drilling nothing has been done, I have several more months to work out specs etc. for everything including the well/pump/storage system I need to put in.

Calculating that I'll use ~ 600 gallons/day average, 17 GPM peak usage. So if I'm reading/researching everything correctly I plan to put in at least a 400 gallon storage tank in the basement. Unless I'm missing something, it does look like in terms of a booster pump something like the CMBE 5-62 is what I should plan to use I want to be able to get ~ 50 psi at ~ 15 GPM at my shower. Maybe that pump is overkill. The tank/pump will be in the basement, my shower two floors up from that.

I plan on getting advice from the sub my builder uses as well in the coming weeks but would appreciate any advice, confirm if I'm on the right track etc.?

 

[Reach4]

8" wide well, 520' deep. static water level 54'.

Try plugging your numbers into this calculator and see if that inspires you: http://www.hydro-terra.com/well-volume-calculator/

 

[tenflyer]

Ok so I do have hundreds of gallons in the bore actually over 1000. I definitely get that. Probably why they had to dig to over 500ft.

What I was thinking though is the pump would have to be at say 300 feet down to have ~ 600 gallons accessible. So instead of the large tank/booster, maybe just get a high GPM well pump with a cycle stop valve? I need to research/understand performance charts of the deep well pumps more, when I glanced (admit it was quick) and I see the charts on depth to water of 300-400 feet the GPM drops a lot so I figured I had to go with the tank/booster.

I'll research more - sorry we just never had a well before been on city supply on all previous houses I have a lot to learn...

 

[Reach4]

Here is some pump info in table form. I am thinking maybe a 2 HP. If the water level falls a lot, you would not be able to take your 17 GPM shower, but you could have a good while in the shower before the water level dropped that much.

I do see there is a problem with you working off of the left side of the tables. Perhaps a "Dole valve" limiting the GPM to 20 GPM would make the pump happier.

 

[tenflyer]

Ok it's starting it click for me! Thx a ton. Looks like I need 3 hp though. Don't mind spending the $$$.

 

[tenflyer]

Making a long story short, further discovery on our lot found an old well dug in 1988. Pulling the original permit shows it is 6" wide, 345' deep, static water level 56' and 2gpm yield. We did verify yesterday by dropping a weighted line w/ balloon the water level does sit at 56'. Going to research getting a well yield test done, and work with the county who originally stated it should be abandoned, about trying to keep this one active assuming the test shows it is a good well.

So this might change what we do, now I have to figure out if we should utilize both wells and stagger the settings slightly or what. I guess this is a good problem to have.

 

[Craigpump]

Surprised no one suggesting hydrofraking that well

 

[tenflyer]

I'm going to ask about hydrofracking. Not sure how common that is in this area but that is a great idea. Reading up on the costs and average yield gains now.

 

[tenflyer]

Craigpump - the majority of the well shaft is a gray schist/mica rock. From what I read about hydrofracking the type of rock is key among other factors of course. I've read some of your posts where you have had some pretty good success - do you have experience in that type of rock by chance?

 

[Craigpump]

We have a lot of mica schist here in our area, coincidently in areas where the wells aren't the best. That said, a good zone Frac using 6000-9000 gallons of water can make a huge difference in well yield.

The down sides?
Mica schist is a soft, flakey rock that can collapse after fracking. Seen that happen more than once.
Because it's in layers, almost like shale and soft, the hydrofraking may need to be done again a few years down the road.

 

[tenflyer]

Ok great to know, thanks for the input. Not sure what I'd be doing w/o this forum.

Maybe I'm overthinking things at this point. I can simply start using just the new well which has over 1000 gallons in the bore, install a 2HP 20 GPM pump at 480 feet or so and a cycle stop valve. I can always add a pump and cycle stop valve in the old well later if I somehow have issues on the first. Then I can consider spending the bucks on the hydrofrack option on one of the two if I need more yield.

I have to remember that the new well especially since it is 8" wide does give us a lot of stored water @ 500 feet deep I just have to get a fairly powerful pump to provide the 20 gpm at that depth and pressure we'd want.

 

[Reach4]

I suggest that you read about upthrust. Maybe try this search in a search engine: submersible pump upthrust dole

 

[tenflyer]

Will do, saw you mentioned the dole valve earlier in the thread I missed that initially. Very confusing, ugh but thanks for pointing that out gives me more to read

 

[Craigpump]

Not a fan of Dole valves. Yes they restrict the flow and thereby reduce up thrust, but they squeal like no tomorrow when they are installed inside the house.

 

[Valveman]

Installing a Dole valve after a CSV will reduce the back pressure on the Dole valve by 100 PSI, and the Dole valve will not make any noise. However, a 20 GPM, 2HP only needs 140' of head to keep from being in upthrust. With a static level of 56', and starting the pump at 40 PSI (92' of head) will keep the pump from upthrusting, so a Dole valve is not needed. The back pressure from the CSV will also help keep the pump out of upthrust.