Construct new well, or UV treat existing?

Discussion in 'Pumps and Tanks Well Forum & Blog' started by PK, Aug 2, 2014.

  1. PK

    PK New Member

    Messages:
    27
    Location:
    Virginia
    We have a 50-foot-deep by 30" diameter bored well that was constructed in 1980. We've lived here for 10 years with no water problems (low pH is corrected by soda ash), until we had a significant downpour early this summer. Our water turned cloudy, and we tested positive for total coliform and e.coli bacteria.

    Since then, I've disinfected twice at 200 ppm and retested twice, and we continue to be positive for total coliform (negative for e. coli). I had a well service company come out last week to inspect the well. After 30 minutes of pouring water on the ground around the well, the well guy showed me a trickle running down the inside of the well starting at about 13 feet down. He said this means we're getting unfiltered surface water into our well. He also said it was his opinion that it was unlikely that it could be repaired.

    I think my two options are now 1) construct a new well, or 2) install filtration and ultraviolet equipment and use the existing well.

    All the local well companies prefer to drill deep wells -- around 250 or 300 feet. I also know that my neighbors with deep drilled wells have complained about stained fixtures, iron, or other water quality issues. So I don't know if a new well would just be trading out one set of issues (bacteria and surface water) for another (minerals, hardness, uncertain production rates), or if it's clearly the better solution.

    My primary goal is to end up with a happy household that enjoys our water -- cost is not the primary concern. What would you recommend for our situation?
  2. craigpump

    craigpump Member

    Messages:
    970
    Location:
    ct
    Drill a well.

    1) UV lights require yearly service to remain effective which is around $350.00 at least here in Ct.

    2) if you have any iron or manganese, it will coat the quartz sleeve and cut down on the effectiveness off the light, so you may have to install a softener anyway to prevent the iron from accumulating on the sleeve.

    3) I have seen many home buyers lose interest in a home as soon as they see a UV light.
  3. Smooky

    Smooky Member

    Messages:
    624
    Location:
    NC
  4. LLigetfa

    LLigetfa DIYer, not in the trades

    Messages:
    4,051
    Location:
    NW Ontario, Canada
    It may depend on the formation and whether or not there is anyone in the area to do it but putting in a liner might be an option. They might be able to gravel pack the lower part and seal the upper part.
    craigpump likes this.
  5. WellPro

    WellPro New Member

    Messages:
    3
    Location:
    Wisconsin
    PK,
    I am a professional with 30+ years of experience drilling wells and installing pump systems. I am in Wisconsin, so I looked up the well regulations for Virginia. It sounds like you have a well casing issue. Regulations require your casing to be grouted to a minimum of 20' and the top of the well needs to be sealed where the casing is above ground. But first off, I am curious why your well is 30" diameter? Do you know who drilled/bored the well and do you have the records? I am wanting to know the well records because it will tell me what your geology is at the well site. This is step #1 in figuring out what needs to done.
    LLigetfa likes this.
  6. Smooky

    Smooky Member

    Messages:
    624
    Location:
    NC
    Bored wells in this area are usually 24 to 30 inches in diameter. About the deepest they go is around 80 feet but some rigs can go 100 foot deep. They are generally considered a shallow well. The boring rig can only bore in the soil not in the rock. Most of the time the casing is 4 foot long concrete tiles that are set in the bore hole. In the 1980’s grout and a slab was not required in NC and probably not in VA.
    Most bored well contractors in this area have gone out of business or switched to drilled wells. They were much cheaper to put in than drilled wells. Sometimes the boring rig hits rock before it hits water. Customers do not like to pay for a dry hole.
    I’ve never seen a bored well contractor do a well log. The well is bored very fast and the casing is set. Most use a mirror do direct the sunlight down the hole so they can see how it looks. If there is water coming in, it is good and they set the casing.


    Here are some examples of what they look like:


    Last edited: Aug 2, 2014
  7. WellPro

    WellPro New Member

    Messages:
    3
    Location:
    Wisconsin
    I've heard of the old bored wells, although they are not typical in Wisconsin. The older wells here are either 5" tin casing or 4.5" to 5.5" clay tile. The problem with clay tile or even cement tile is usually at the joint where each section meets the next one. That is where a leak can occur. Also, not a good way to seal up the top of a 30" cement tile to make it water-tight. In my opinion, a new 6" steel cased well should be drilled according to current regulations. And don't forget to properly abandon the old borehole because it is a direct conduit to the aquifer. Safe bacteria free water is worth everything even if you end up having to deal with a little iron and acidity.
  8. LLigetfa

    LLigetfa DIYer, not in the trades

    Messages:
    4,051
    Location:
    NW Ontario, Canada
    My guess is that the well cannot simply be abandoned and that it would need to be sealed. I think it may cost close to the same to remediate it as it would to seal it up.
  9. PK

    PK New Member

    Messages:
    27
    Location:
    Virginia
    I appreciate the suggestions so far. I can live with either the annual cost of UV treatment or the up front cost of digging a new well. I know I have to open my wallet in this situation.

    I suppose I could pose my question differently. I know I'll have to treat my water, whether I dig a new well or keep the old well. With the old well, I'd have to install UV treatment in addition to the soda ash. With a new deep well, I don't know what I'll have to treat for.

    I've never had a well drilled before, so I don't know whether we'd end up better off. I hear all kinds of stories about iron, hardness, other contaminants, flow problems, etc. from people on other wells. We have none of those with our shallow well. I just don't know whether we're likely to end up better off by treating the old well with UV or by rolling the dice on a new well.

    I figured folks out here with more experience than I have might have useful views, and I appreciate the help.
  10. LLigetfa

    LLigetfa DIYer, not in the trades

    Messages:
    4,051
    Location:
    NW Ontario, Canada
    It comes back to the water turning cloudy. UV is much less effective in cloudy water and of course does not solve the problem of cloudy water. The well needs to be remediated or sealed shut and a new well drilled.
  11. LLigetfa

    LLigetfa DIYer, not in the trades

    Messages:
    4,051
    Location:
    NW Ontario, Canada
    The first video shows a well being deepened. The now bore is smaller diameter than the existing casing so I'm guessing they will use smaller casing on the lower portion.

    The second video showing them daylighting the casing and grouting it with concrete, I find questionable. It looks like they are only extending the old seal by about a foot or so. Hardly seems worthwhile.
  12. Reach4

    Reach4 Active Member

    Messages:
    2,387
    Location:
    IL
    http://www1.agric.gov.ab.ca/$department/deptdocs.nsf/all/wwg408 seemed to be a pretty good write-up when I was searching to find the distinction between a bored well and a drilled well.

    Note that another way to deal with coliform is chlorination, contact tank, followed by a backwashing activated charcoal filter to remove the chlorine. This should also remove or greatly reduce the cloudiness, I would hope.

    It would be nice if you could find a driller capable of sealing the casing by injecting suitable material outside the casing into the appropriate depth.
  13. LLigetfa

    LLigetfa DIYer, not in the trades

    Messages:
    4,051
    Location:
    NW Ontario, Canada
    Given that the test showed the water entering at about the 13 foot depth, I think attacking the problem from the outside may be a challenge. One would probably have to put down a series of 20 foot long small casings around the perimeter and pump in bentonite slurry while they are being pulled back out.
  14. craigpump

    craigpump Member

    Messages:
    970
    Location:
    ct
    UV lights and chlorination systems are band aids that can kill a potential home sale down the road.

    Reworking the well with a string of liner, crushed stone and a 3-4' cap of chip bentonite on top of the crushed stone seems like a big expense with no guarantees that the coliform won't migrate to a lower zone and recontaminate the well.

    Excavating down around the outside and filling that cavity with a slurry would be expensive also with no guarantees the coliform won't migrate.

    I would seal the bore with chip bentonite and sand after drilling a new well.
  15. WellPro

    WellPro New Member

    Messages:
    3
    Location:
    Wisconsin
    Craig,
    You and me are on the same page. I have been drilling wells for 30 years and ere is only one way to remedy this problem...the right way. Drill a new well and abandon the old one. And yes, the old well can be abandoned, people. By not properly abandoning the old well according to state regs, you are introducing bacteria into the aquifer and that can ruin other peoples wells.
  16. akcooper9

    akcooper9 New Member

    Messages:
    22
    Location:
    North Texas
    I agree with everyone else. Abandon the old well and drill a new one.
  17. LLigetfa

    LLigetfa DIYer, not in the trades

    Messages:
    4,051
    Location:
    NW Ontario, Canada
    I did not get into specifics, but that is not how I would do it. I would gravel pack only the bottom 20 feet and seal the top 30 feet. Makes no sense to only seal the top 4 feet when the test showed the surface water entering at 13 feet. You are correct however that the contamination could still migrate down the outside of the old casing and enter the well below the 30 feet of seal.

    I suggested punching down small lines to pump in the slurry, not daylighting around the well.

    I am not a well driller but I have worked on drill rigs on construction sites where we used bentonite as a lubricant and seal.

    Just curious what you would charge to abandon and seal a 50 foot deep 30 inch hole.
  18. akcooper9

    akcooper9 New Member

    Messages:
    22
    Location:
    North Texas
  19. craigpump

    craigpump Member

    Messages:
    970
    Location:
    ct
    Yeah I know how to grout through tremie lines... Can you say pain in the a$$ ?

    How much would I charge? I'd hate to think about it
  20. PK

    PK New Member

    Messages:
    27
    Location:
    Virginia
    I think the band aid concept may be the central issue for me. Does that mean installing equipment to remove bacteria is a band aid, but installing equipment to remove iron, sulfur, hardness, or other contaminants is not?
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