What are the main sources of well water contamination.

Where do well water contaminants come from & how do they get into the well. Knowing the answers can help prevent or cure contaminated well water.

Page top photo: this steel well casing top was close to ground level and could be lifted right out of the ground. So at this well there was a real risk of well water contamination.

Where Do Ground Water Pollutants & Thus Well Contaminants Come From?

Here the EPA (with some added commentary) describes common sources of well contamination. We have added links to more detailed diagnostic articles about individual well water contamination problems.

Article series contents

• WATER POLLUTANT SOURCES
  • WATER DEBRIS, STAINS - SOURCES
  • WATER TASTES - SOURCES
  • WATER SMELLS, ODORS - SOURCES
• WATER ODORS, CAUSE CURE - separate article
• WATER POLLUTION - NATURAL SOURCES - separate article
• WATER POLLUTION - HUMAN SOURCES - separate article
• GROUND WATER CONTAMINANTS - separate article

Sources for more information and help are also listed. [Editing for clarity by DF are marked by brackets or italics] Initial Source: EPA 816-K-02-003 January 2002. Also see How To Spot Well Contamination Problems later in this article series.

Understanding and spotting possible pollution sources is important. It's the first step to safeguard drinking water for you and your family.

Some threats come from nature. Naturally occurring contaminants such as minerals can present a health risk. Other potential sources come from past or present human activity - things that we do, make, and use such as mining, farming and using chemicals. Some of these activities may result in the pollution of the water we drink.

Several sources of pollution are easy to spot by sight, taste, or smell. (See Quick Reference List.), however many serious problems can only be found by testing your water. Knowing the possible threats in your area will help you decide on the kind of tests you need.

Visual Evidence of Water Contamination Problems

Sources of Visible Water Contaminatiom-like scale, stains, or floating dirt/debris

• Scale or scum from calcium or magnesium salts in water.
  
  At WATER SOFTENERS & CONDITIONERS we discuss formation of scale in water softeners;
  
  at CLOGGED SUPPLY PIPING we discuss clogged water piping due to scale formation.
• Unclear/turbid water from dirt, clay salts, silt or rust in water
• Green stains on sinks or faucets caused by high acidity
• Brown-red stains on sinks, dishwasher, or clothes in wash points to dissolved iron in water
• Cloudy water that clears upon standing may have air bubbles from poorly working pump or problem with filters.

Sources of Water Tastes as Evidence of Water Contamination

• Salty or brackish taste from high sodium content in water
• Alkali/soapy taste from dissolved alkaline minerals in water
• Metallic taste from acidity or high iron content in water
• Chemical taste from industrial chemicals or pesticides

Sources of Water Smells that may Indicate Water Contamination

For detailed advice on diagnosing and curing water odors

see WATER ODORS, CAUSE CURE.

Sources of Sulphur or Rotten Egg Smells in Water

• A rotten egg odor or sulphur odor in water
  
   can be from dissolved hydrogen sulfide gas or certain bacteria in your water.
• A rotten egg or "sulphur odor" in drinking water may also come from the water heater 
  
  and may be easy to fix. If the smell only comes with hot water it is likely from a part in your hot water heater. [
  
  The water heater's sacrificial anode, a rod sticking down into the water heater tank, is intended to reduce water tank corrosion and thus extend water tank life. But when the anode is badly corroded or dissolved itself, this condition can be a source of smelly water.
  
  Check for this condition before doing something more expensive to address water odors. We most often notice this odor when the home has been unoccupied for some time and the water heater has become deteriorated.
  
  Key is that the odor is only noticed when running the hot water--DF]
• We discuss the hot water tank sacrificial anode and dip tube in more detail
  
  at CHECK the SACRIFICIAL ANODE & DIP TUBE of Your Water Heater Tank. [DF addition/edit]
• A sulfurous smell or rotten egg smell may also be due to the combination of loss of oxygen in water (hypoxia), or low oxygen levels, combined with algae
  
  which feeds and then dies in rivers, lakes, ponds, streams, or even large areas such as the Gulf of Mexico where agricultural runoff in the Mississippi river results in high nitrogen levels in water entering the Gulf.
  
  In 2008 the "dead zone" in the Gulf of Mexico was reported by the New York Times as likely to form a smelly sulphur-smelling zone of roe than 8,500 square miles.
• We provide a detailed list of sewer and sulphur gas odor sources
  
  at SOURCES of SULPLHUR ODORS in BUILDINGS

Sources of Other Odors in Water

• A detergent odor in water
  
   and water that foams when drawn could be seepage [into the well] from septic tanks [or other groundwater] into your water well.
• A gasoline or oil smell in water
  
   indicates fuel oil or gasoline likely seeping from a tank into the water supply.
  
  [We found a property at which an owner was using an old "abandoned" drilled well casing to dispose of his used motor oil.
  
  This is an example of why it's a good idea to properly seal abandoned wells, making it unlikely that an un-used well will become a pipe for contaminants to be sent directly into the local aquifer--DF]
• Methane gas or musty/earthy smell in water 
  
  may be from decaying organic matter in water.
  
  [We've had reports, especially from mining areas such as portions of Pennsylvania in the U.S. in which underground methane was seeping into the well through rock fissures.
  
  One client could on occasion light gas coming from their kitchen faucet! Be careful, such conditions are dangerous and risk explosion or fire--DF]
  
  See METHANE GAS SOURCES for details about sources of methane gas in and around buildings and in the water supply or in wells.
• Chlorine smell in water 
  
  may be from excessive chlorination [or from improper or inadequate water treatment systems that have stopped filtering excessive chlorine in the post-processing step after using a chlorinator to kill bacteria in a water supply. -DF.]

For detailed advice on diagnosing and curing water odors

see WATER ODORS, CAUSE CURE.

Watch out: Many serious problems (bacteria, heavy metals, nitrates, radon, and many chemicals) can only be found by laboratory testing of water.

• FLOOD CONTAMINATED WELL RESTORE & PROTECT explains the importance of protecting a well from polluted groundwater, of protecting groundwater from accidental pollutaion through open wells, and also how to return a well to operation and use after area flooding.
• WELL FLOOD DAMAGE REPAIR describes how flood waters can cause well and water system piping contamination and what to do about it before using well water after area flooding.

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Reader Q&A - also see RECOMMENDED ARTICLES & FAQs

Trouble with muddy rusty water from my well

Replaced my well pump about 10-12 years ago, 125' well, once in a while I would get some really bad rust/mud color looking water when I turned on the faucet, along with a black

Gritty type substance in the sinks and tubs, sometimes it would get so bad I had to clean out all the faucet inserts, and tub faucet inserts, replace the whole mech. inside the toilet because it became clogged and wouldn't fill the toilet, this happened about every 9-11 months?

now its happening quite often like every couple months, If I catch it and let things set idle for a couple hours we have no problem if someone forgets and draws water to do laundry or dishes, they pull all the love thru the system and we have problems, what is happening? do I need a new well ? my current well to be dug deeper?

or another new pump? dont know where to start looking if so whats a ball park figure if I need my well to be dug deeper?

I just got everything cleaned up from our last episode/ not looking forward to another one! Please, any help in what to do or look for will be greatly appreciated !!
Bill On 2016-12-10

Is my pump set too low in the well?

I'm now wondering if my pump is setting too low in the well? since the brown like water, mud is showing up again all of a sudden?

now I have no water and pump wont run hopefully it has a protection switch on it but if not guess I'LL BE PULLING THE PUMP my follow up question how do I know the depth to lower my PUMP into the well so as to NOT have it setting on the bottom and collecting mud and debri from the bottom of the well?

Someone told me to pull it inspect the pump if it runs and is not burnt up cut off about 2 feet of water line and reinstall the pump is this a reasonable amount of piping to cut off?
Thanks Bill On 2017-01-03 by Bill -

by (mod) - causes of brown well water

Brown water: I'd have the water tested so we know what we're looking at: a contaminant, mud or silt, rust debris.

For example, low water in the well can cause the problem you describe but so can the problem occur from a damaged well casing (inspect the casing with a camera as described at WELL BORE CAMERA SYSTEMS) or even from a well piping leak that squirts and stirs up silt in the well.

You may want your well service company to run a camera down the well casing to look for damage; for example, a casing leak can cause new levels of mud and dirt in your water supply.

See WELL CASING LEAK REPAIRS 

So let's do some diagnosis (inspecting) before going to anything costly. Sure you could try just pulling up the pump 2 feet as that's cheap. But surely something has changed.

by Bill - found burned up submersible well pump wiring

Ok, I pulled the pump and to my surprise I found that the two wire leads to the pump had been burnt completely off about 60 feet deep or so, I didn't notice much tangled or twisted piping or wiring as i was pulling the pump up but I'm almost 100% sure it had been rubbing the well casing and one thing led to another, I repaired the wiring, then we put the 3/4 HP pump in a 55 gal drum with water it started to like bubble at first,

but then all of a sudden it started pumping really well, it was pushing water out of the pitless adapter and the drum water was going down at a really good rate, so I shut it off, cleaned up things best I could,

I then though ok I'm going to do that test I read about here on your site, I placed a piece of copper tubing about 16" over the 100' x 3/8" nylon rope I had and also tied the other end to another piece of 100' para cord I had, lowered the weight down the well until I ran out of the 100' of nylon rope,

and btw about 3/4 the way down I'd say 80' or so I could hear it hitting water, anyways I lowered the rope with the para cord tied on to the end another 50' feet or more and it kept going down more and more,

I now had approx 150' to 175' of rope down the well with the weight on it and it wasn't stopping? ( my well cap is stamped 125' -- 108' of casing, rated @ 10gpm ) so I'm thinking wow, my water amount should be ok.

So I ended up cutting off 3' of water supply piping and lowering the pump back down and see what happens..
I turned on the pump and within 30-40 seconds I had water pumping in the house (YaY!! lol) it was not muddy or really rusty looking

it was more like very cloudy like when you disturb a pond by walking in it and it takes a while for the water to settle down again to become clear... this is what I though was going on anyways,

I noticed the water had been actually clearing up hour after hour so I decided to let it set and not pull any water until the next morning, by then I ran water and it took about 3 mins and it was almost crystal clear,

a day late now it is crystal clear, I'm hoping cutting off 3' and raising the pump height is going to solve my problem (at least until warmer months lol) seems the longer it goes the clearer the water seems to be, we usually don't drink the well water unless we filter it anyways so im happy to have it running again at least for toilets and showers!!

I do have a question or two though to ask,

1. Someone told me to put a couple gallons of bleach down my well then run the pump until I could smell it inside at the faucets, then shut it off and let it stand for a while then later run it off?

Would you suggest this and how many gallons of Clorox should I use, another question related to this one is Since I have a pool I have some 3" chlorine tabs since we don't drink the water anyways would it hurt to drop one or two chlorine tabs down the well and let them dissolve?
I also forgot to tell you, when i used my high powered spot light to look down the well I could actually SEE water way way down, and I thought at one time or so we could actually see it moving??

2. Is this because we just experienced two days of rain and the water table is actually very high right now, or is it possible that the well water level could actually RISE over time?

I'm hoping the water lvl hasn't risen to the actual depth of the casing @ 108' because when I pulled the pump I measured approx. where I thought the water piping shown to be wet from actually being in the water and it was a surprising 30' from that point to the bottom of the pump.

The casing as far down as I could see with my spotlight was Dry, until where I thought I had seen water but I could not tell if the water had actually been UP to where the casing had been or below it, just could not make that out

Thank You for your help in advance I really appreciate it a lot, I was just discouraged when at first I didn't get an answer I just couldn't find anyone or any information online about my problem, and I didn't know where to turn..Thank you agian!
Bill
Ps; I apologize for the length of this post I just tried to give you all the info I could on the problem! - Bill On 2017-01-06

by (mod) - causes of submersible well pump wiring damage

Bill:

Thank goodness nobody got fried.

Adding:

Thanks for the details: what you report will help other readers.

There is a problem with submersible pumps torquing or twisting the pipes and wiring in the well at the start and less but also at the end of each pump-on cycle.

Components sold to address this problem include torque dampers and spacers to keep pipes and wires from rubbing on the casing - a particular problem in deep wells - and also devices that absorb pump torque at on-off cycles.

You'll want to flush the system until you don't smell bleach. If you have trouble getting rid of the bleach smell you may need to wash down the sides of the well casing, or empty out water pressure tank and water heater tank.

DO NOT use chlorine tablets in a well. See https://inspectapedia.com/water/Well_Chlorination_Shocking_Procedure.php

YOu might see water moving because water is running into the casing from below the water surface. If the casing were damaged you might see also ground water (unsanitary) running down the casing into the well water

by Bill - well casing ok, added rings to protect well wiring

Ok, As far as I can see the casing looks like it's in tack and dry as far down as I can see with my high powered spot light...

This is about day three now and the water has cleared up completely(yay)!! I haven't put anything in my well so far as far as
bleach, was waiting until I heard back about your thoughts on it, so

I did add a couple of the plastic rings to my water line and also installed a Submersible Well Pump Torque Arrestor, which
wasn't present before, so hopefully everything is now going to be ok!

I have extensive knowledge in wiring and plumbing as being a self employed General Contractor for the last 40 years, I just didn't really get into anything involving water wells and such, as noted earlier,

I had replaced our pump over 10 years ago but that only involved cutting and splicing the wires for installation of the new pump itself along with the heat shrink material used, At that time I didn't have any problems with my Water just the dead pump!

So this has been an experience for myself I'll continue to monitor my water and the condition of it now that I have a little more understanding of how things all work, thanks to your help here on your site,,,
Thanks for all your help!
Bill

by (mod) - sanitize the well after working on it

Thanks for the feedback, Bill.

Good going.

If you have need to sanitize or shock your well please see WELL CHLORINATION & DISINFECTION 

And you will see that the use of liquid household bleach can work just fine in the right concentration. Our article will tell you how much bleach to use based on the static head or volume of water in the well casing. It's not that hard to figure out.

However I never want to use pool chlorine tablets in a well. I'm not sure that we know what the effective disinfectant concentration would be. But worse people who have tried that have had a hell of a hard time getting the chlorine out of the well because you have this solid block that sits at the bottom and deserve very slowly.

Strong odor in water after replacing water heater & adding a filter etc.

I have put in a new water heater, added a inline filter, added clorine to well, but still have a very strong odor in my water. help please - On 2020-02-12 by jerry -

Reply by (mod) -

Jerry

We need to have an idea about what sort of odor to make even a wild guess at what's wrong.

For example, adding chlorine to a well may do nothing if the odor source is sulphur in the water supply, nor if the amount added was insufficient, nor if the contamination is a persistent source.

Have you had your water tested for bacteria?

Is the odor present at both hot and cold water faucets?

See the water supply odor diagnostic steps at

ODORS IN WATER

What's causing black water coming out of faucets

Last week, my neighbor said he got black water coming out of his faucets, and after running the water for awhile, it cleared back up.

He asked me about my water....that has never happened to mine. I asked another neighbor and he said this has happened to his water once in a blue moon, he runs it awhile and it clears up until the next time, maybe 6 months or more later.

There is a gas well 100 feet from his well. All of our wells are within 500 feet of one another and were all drilled in the late 60's, early 70's. What could be causing this? (Nov 16, 2014) Nancy

Reply:

Nancy

Black water, if suddenly coming from a well source, may indicate a cracked well casing or some other leak into the well or well piping system. I've seen this happen to a long-established shallow well when there was nearby road blasting.

Black water can also be actually caused by sulphur, sediment, or other external problems.

I suggest that in that case one should collect a sterile bottle sample and take it to a local water testing lab for analysis.

The findings can help direct both further investigation, and if needed, water filtration and treatment.

...

Continue reading at WATER POLLUTION - NATURAL SOURCES or select a topic from the closely-related articles below, or see the complete ARTICLE INDEX.

Or see these

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• SWIMMING WATER TESTS
• WATER POLLUTION - HUMAN SOURCES
• WATER WELL CONTAMINATION HAZARDS
• WELL WATER CONTAMINATION: CAUSES, CURES - home
• WATER POLLUTION - NATURAL SOURCES
• WATER POLLUTANT SOURCES
• WATER POLLUTION - HUMAN SOURCES

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