Monday, May 18, 2015

Disinfecting My Well and Plumbing System

This spring when I tested my well water I found coliform bacteria present. This is a problem that should be address immediately, but is not a reason to panic. My well was found to be contaminated with coliform but not E. coli, so I have a nuisance bacteria problem and the source may be infiltration from the surface from rain or snow melt. Typical causes of this are an improperly sealed well cap, failed grouting or surface drainage to the well. Standard protocol is:
  1. Carefully check the well and water system for points of contamination and retest to verify the result making sure to use proper sampling procedures. 
  2. If the sample still tests positive for total coliform then treat the well and plumbing system with 50-200 ppm chlorine for 12-24 hours to disinfect system. Then flush the chlorine from the system.
  3. Retest the water after the chlorine has left the system in about 10 days to two weeks. Confirm the testing again after the next big rainstorm. If coliform bacteria remains “absent” you’re done. If not, then it is time to install a long term disinfection system.
You disinfect a private water well and plumbing system by circulating a concentrated chlorine solution throughout the system. The level of chlorine to use is between 50 ppm and 200 ppm (parts per million) depending on which University extension office is asked. I plan to use a bit over 100 ppm which gives me a little leeway because I am estimating the volume of water needed for the household plumbing. Be aware that too concentrated a solution or too weak a solution will not be effective. Do it once the right way. See the chart below to estimate the amount of chlorine you will need or the Virginia Tech or Minnesota guides.


I estimated I needed about 1 ½ gallons of chlorine because my well is 150 feet deep, the water level is around 8 foot down (each foot of a 6 inch diameter well is 1.47 gallons of water), my pressure tank holds about 15 gallons, my hot water heater holds 75 gallons and I have lots of piping in this big house. I have about 208 gallons of water in the well and probably another 150 gallons of water in the plumbing fixtures and pipes. For 100 ppm concentration of chlorine you need about 3 pints of chlorine per 100 gallons. A gallon and a half of chlorine brings me in around 114 ppm depending on how close I am to a good estimate of the amount of water in the plumbing system. I purchased more than twice the amount of chlorine I needed in case I needed to run some of the water off to get clear water or if I cannot get high enough chlorine concentration at the faucets. Also, I bought HTH chlorine test strips. While it’s pretty easy to smell the concentrated chlorine solution, the test strips are necessary for testing during flushing the chlorine out of the system.


I am going to immediately disinfecting my well because treating a well with chlorine also cleans out the mineral deposits in the well and eliminates (or reduces) iron reducing and sulfur bacteria that I have had problems with in the past. I was actually thinking of treating my well with chlorine sometime this year anyway. There is no time like the present. I started yesterday morning by repacking the soil around the well pipe to make sure it flows away from the well as much as possible.

First thing I needed to do earlier this week was develop a plan and find someone to help me. If I could just hire it out and be assured that it would be done neatly and right, I would. That is just not the way the world works. My very kind plumber was able to fit me in his schedule for two mornings and is going to work with me on this. I initially called a well driller, but they could not get me on the schedule for another 3 weeks and they tend to be really muddy and messy. My plumber is perfectly capable of helping me with anything I can’t do - loosen the bolts on the well cap for me- and while I add the chlorine to the well and wash the well cap and use the hose to recirculate the water he will drain the hot water heater and turn it off. I want the hot water heater to fill with chlorinated water to disinfect the tank, but I do not want to heat the chlorinated water- that is not at all safe in an enclosed area. During the waiting times, the plumber cleaned out some drains, tested the sump pumps and couple of other little things that needed to be done.

The first thing you need to do is purchase all your supplies and prepare. I bought or had on hand: a plastic tarp, 3 ½ gallons of plain unscented Clorox bleach (3 gallons is about twice what I need to disinfect my well and plumbing), an 8” diameter funnel, rubber gloves, a 3 gallon bucket (I can’t easily lift a 5 gallon filled with water and chlorine), chlorine test strips and a clean and relatively new hose. In addition, I bought 6 gallons of bottled water (to carry us while we have no water to use and make sure that our coffee and tea do not have any chlorine residue to spoil the taste), new refrigerator filters, and coliform home test kits for use in a couple of weeks.

Wednesday, I did laundry. Cooked two days of food, and ran the dishwasher. Thursday morning I took a bath, made three pots of coffee that I put into thermoses and put on old clothes, my indestructible old LL Bean “Ducks” and a pair or safety glasses to protect my eyes. I don’t want to be splashing chlorine solution in my eyes. Also, you should wear rubber gloves. Then I hooked up the new hose and laid the open end on the tarp.

Disinfecting or shock chlorinating a well and plumbing system is really a two person job especially when one of the people has a touch of arthritis in her 60 year old hands and cannot loosen bolts. I began by filling my bucket with some water and chlorine then turning off the power to the well. My assistant with younger and stronger hands took off the well cap, and then went to turn off the hot water heater and drain it. The hot water should be drained into a floor drain not the septic system and cut off the water valve so that the hot water heater does not refill until you are ready. This is where it was really helpful that I hired Chris Jones from Chantilly Plumbing to help me. Chris and Ron from Chantilly Plumbing installed my new hot water heater last fall and all I had to do was explain what I wanted done and I knew he would do it neatly and correctly.

While Chris was draining the hot water heater I was washing and disinfecting the well casing and well cap, (this amounts to scrubbing them with a new dish brush dipped in chlorine solution. Then I carefully examined the visible pump wires for damage or worn spots. I wiped off the wire using a clean rag dipped in the chlorine solution. Then I put the funnel in the well an poured the first bucket of chlorine and water solution into the well. I went with about a 2 to 1 water to bleach solution some universities recommend a 4 to one water to bleach solutions some say you can just pour the bleach in- I use 2 : 1. Then I went down to the basement turned on the power to the pump so I could draw more water and mixed up the rest of the chlorine and water and carefully poured it into the well.

Since the well is the delightful combination of water and electricity, it is always best to shut off the circuit breaker before you open the well, pull aside the wiring and begin pouring chlorine in. Mix the right amount of chlorine with water in a bucket, pull aside the wiring (and look at it to make sure it all looks sound) place the funnel in the top of the well and pour in the chlorine solution. Next it’s time to turn the power back on at the well, and use the hose to get the chlorine solution fully mixed and distributed in the well. All you do is put the hose in the well dropping it past all the wires and turn it on. The water with chlorine is drawn by the pump at the bottom of the well, pumped up the well and out to the pressure tank in the basement. Then it is pumped out the hose and back into the well. It is important that no water is being used in the house. While the hose did that, I carefully washed the well cap in the bucket with a chlorine solution, wrapped the well cap in a clean area of the tarp and went to have a cup of coffee. Read the paper and kill about half an hour or so. After about 30-45 minutes go check the well.

I pulled out the hose and ran a bit of water into the white bucket I used earlier. A bit of crud and rust came up after, so I flushed the well by running the hose onto the gravel for about for about an hour. Then I added about half a gallon more of chlorine to replace the chlorine I ran off. Then I recirculated the well for about an hour while we had more coffee. After an hour I checked the appearance of the water in my white bucket, smelled the pronounce chlorine smell and was satisfied. (If you have never chlorine shocked your well you may have to draw off water more than once.) I pulled out the hose, turned it off and Chris bolted the well cap back in place.

Then it was into the house to fill the hot water heater (still turned off) with chlorinated water. I set up the hoses for flushing the well the next morning by daisy chaining them to run into a gravel area to prevent killing off my lawn while Chris handled the hot water heater. After the hoses were set up I went into the house and Chris and I ran every faucet until we could smell the chlorine and the test strips told me there was chlorine. After a while everything smells like chlorine so the test strips are helpful.

Every sink, the water line to the refrigerators, every toilet, the tub, the showers, the dishwasher and the washing machine all had chlorinated water drawn into them. Then it was no water for 12-24 hours and I went to get a manicure and pedicure. Hey a girl deserves her treats. After 16 hours just before dawn Friday the hose was turned on and left to run for the next 12 hours. It may take you much less time than it takes me to flush my well. I cannot run my well dry-it recharges faster than I can pump. So, I need to keep diluting the chlorine solution by pumping the well to rid my well of it. After about 8 hours the chlorine tested below about 1 ppm and it was time to let the hot water heater refill and turn it back on.

Once the hot water heater was up and running it was time to open each faucet in the house and run it until the water tested free of chlorine. Be aware the hot water will sputter- big time- until all the air is out of the system. Flush all the toilets, change the refrigerator filter cartridges and dump all your ice.

I’m done. A wee drink is in order. It will be two weeks or more before I can test my water for coliform bacteria and know if this solved my problem. Tomorrow we are leaving for a couple of days, so I am going to goose the septic system with some bacteria to make sure that the chlorine that found its way into the septic system did not cause a bacteria die-off.

1 comment:

  1. That was a long read but worth it. well documented.

    ReplyDelete