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Slow well replenish rate...to build or not to build?
We've resolved this so I prefer to delete the info, thank you for your help!
Last edited by rinibean; 09-11-2012 at 05:56 PM.
with a 37' deep well with water at 21'... thats a big hole to have 350 gallons in reserve. someone else can do the math, but i'd think it would have to be something like 20+ inches in diameter.
what are other people using in the area? is there no possibility of a deeper well with more water?
You need to talk to a driller, not a builder. Let them tell you what to expect.
My guess is the builder skimped out and got the cheapest guy he could find, and then when he couldn't get the first well to work he made a 2nd bad hole.
You should be shooting for 5-10 gallons per minute minimum. Anything less than that and it's going to have to be managed with more equipment.
I believe Porky resides in VA, maybe he has some additional insight.
Here in Ct there are state minimums for well yield, for example, a 6" well that yields 1 gpm must have a storage capacity of 400 gallons or 375' of storage which ever is greater. Unless the well meets state minimums, the town will not issue a certificate of occupancy. I would bet that Virginia has similar regulations.
Last edited by craigpump; 09-08-2012 at 04:13 AM.
Like Texas Wellman said, these are shallow wells dependent on local rainfall! They were bored close to each other because it was convenient! I doubt that there have even been well permits for these bored holes. However you will find that out when you obtain an occupancy permit. Today most bored wells are frowned upon in many states because they are unreliable and unsafe. Even though they cost more I would prefer a deep well drilled by a licensed driller!
Porky Cutter, MGWC
(Master Ground Water Consultant)
I am familiar with the neighborhood you're talking about, and I think I've heard this story. You are bulding in a tricky area......for the rest of the forum...this neighborhood is in a tricky area at the interface between the Virginia Coastal plain (mud rotarty screened wells), and the Piedmont for open hole rock wells. Deep well water may or may not be available. I have a method that I've used in similar areas with great results, to obatin water from the shallow well zone. I'm not sure what the reluctance is, but I have made this offer to 3 major home builders in the neighborhood, and I make it to you. I will drill and test a well anywhere in the neighborhood, and GUARANTEE it to produce 5 gallons per miinute for a 24 hour test. If it doesn't produce, I will abandon the well and leave at no cost. The current wells in the neighborhood are 30 concrete cased, no bottom...not gravel packed, and probably not grouted much. I am offering a screened, gravel packed, grouted well that I've hod great success with in nearby areas. As far as long term concerns, this aquifer is subject to seasonal fluctutations in water level as it directly recharged by rainfall. I do a lot of work with VA DEQ and the greatest fluctuation they have reported in drought conditions is a 10-12' change in water level, so if we can install an efficient well that can tolerate 10-12' in drawdown, you will be alright.
Meant to type 30" concrete cased wells.....they are contructed with 3' tall sections of 30" ID concrete stacked inside a roughly 48" borehole. As for minumums....Virginia just passed new laws for minumum welll yield and storage. A well producing more than 3 gallons per minute needs no additional storage. Wells less than 3 gpm need 150 gallons/bedroom storage per bedroom. I drill mud rotarty wells in the coastal plain. Properly installed screened, gravel packed wells in the Virginia coastal plain generally produce >50 gpm with 20' of 4" screen. The normal residential installation is a 10 gpm pump, and that generally has less than 5' of drawdown, so storage in the well is completely unnecesary.
We've resolved this so I prefer to delete the info, thank you for your help!
Last edited by rinibean; 09-11-2012 at 05:57 PM.
Let some others weigh in....the fact is, with a well and water system you either need storage, or sustainabe yield.....I personally would rather have a 10 gpm well with no storage, than a 1 gpm well or 2gpm well with even a million gallons of storage. Simpy put, no matter how much storage you have, if the well is only capable of a small yield, you will run out if you consume more than it produces....like a leaking toilet, or sprinkler left on, you will run out. I know they tried drilling deep rock wells in the neighborhood, with poor resuls. I am not sure if they drilled mud rotary deep wells....I am not sure it they would produce, but would have to do a test hole and a geophysical log myself to offer an opinion on that.
So with 5 bedrooms, we're required to have 750 gallons of storage then. Does the standing water in the well count as storage, or is a basement tank required? Or, since we have two wells that will be combined to give us around 3.1, does the law requiring storage not apply?Originally Posted by VAWellDriller
Arguing about the minimum and whether it is county, state, or some other AHJ, is moot. Assuming that you can buy/build and your financing is not contingent on well production, if you end up with a poor producer, you would not get a good price when trying to sell.
When I built in '98, I had to certify my well could produce 5 GPM before I could get a building permit and financing. I grew up on wells that did not produce enough and we had to ration, so having and endless supply now is a pleasure. I have a 6" drilled mud well that goes down to bedrock as do many of my neighbours. One neighbour to my North ran out of water with his mud well and had a 300 foot rock well drilled at $48 per foot. Some folk around here had to go down more than 600 feet.
Regarding the 150 gallons/bedroom/day storage.....it can be any combination of storage inside or outside the well.
LLigetfa --- So do you have a screened well, or is it just cased to rock and then open hole?
Cased to within a foot of the rock with no screen, just the bottom of the open casing with crushed stone dumped in to hold back the mud. The formation is clay to within 5 feet of the bedrock, then fine sand/gravel glacial till. It took a lot of work to develop it to where it is now.
Strange construction.....not sure why they wouldn't screen the sand/gravel????
I'm not a well driller so cannot answer that but will take a stab at it. I don't think they intended it to be a mud well. They originally welded on a drive shoe probably with the intent on setting it into the bedrock in anticipation of it being a rock well. I think they drove down the casing as they went, not knowing the formation until after they passed it. I'm guessing they didn't want to pull up all the casing to add screen to the last 5 feet of it and thought the glacial till would be stable enough to be the screen.
They did not actually develop the well and only pumped it at 5 GPM to satisfy the minimum requirement. After I built the house I put in my 10 GPM pump, it sucked in the mud and I had to get the driller back to flush it out and set the gravel pack. It filled back in with mud again and I augered it out by hand and developed the well myself after the driller did a bunch of no-shows.
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