Well Water Turned Nasty?

The science of well and water heater maintenance in a sulfur-rich environment.

It’s a common problem here in the west, particularly those of us with well water. Your water is clean and clear and amazing, and then all of a sudden, springtime comes and something terrible happens. Your water begins to smell bad, taste weird, and turn a yellowish color. Over time it gets worse and worse and you either decide to live with it, or you call a well company to fix it.

You can take care of it yourself if you understand what is happening and what steps you can take to prevent the problem and deal with it when it occurs. This information is primarily for those of us mountain folk with deep wells. Some people have a stream running through their property or other water source that allows them to use a shallow well. Shallow wells are susceptible to many more contaminants than deep wells, and require more aggressive filtration and treatment as a result.

Those of us with deep wells ‘usually’ have very clean water. As surface water penetrates the ground, it enters fissures (cracks) in the rock layers and slowly trickles through them. As it trickles through the fissures, impurities are leached out of the water (they adhere to the rock), so that by the time the water reaches aquifer depth, usually any bacteria or other organisms, and most minerals, are long gone.

During the spring something different happens. The high rate of snowmelt creates surface water pressure which pushes water through the rock fissures, causing it to move too fast to leach out all of the impurities. Some impurities end up making it into the aquifer, and this is where our trouble begins.

Our water has a slight amount of sulfur in it. It’s such a small amount that it is completely harmless and does not add odor or color to the water. Normally very little sulfur gets to the aquifer because most of it is leached out, but during the spring snowmelt significant amounts can reach your well. The sulfur itself is not an issue, but it attracts a type of bacteria known as ‘sulfur-eating bacteria’. It is a weak bacteria that is harmless when ingested but creates several annoyances. As it eats the sulfur, a chemical reaction takes place that makes the water taste and smell bad and turn yellow. The water at this point is also slightly corrosive, which can cause plumbing components to fail if it is not treated.

The sulfur eating bacteria thrives in your well as long as there is a tiny supply of sulfur for it to feed on. It thrives even better somewhere else… Your water heater. It has taken a good deal of trial and error for me to learn how to treat both my well and water heater, so I wanted to share this information with the rest of you.

The only chemical you will need is chlorine. Some people use regular laundry bleach, and this does work fine. Many companies that specialize in well systems also sell chlorine pellets. They are a little larger than pea sized and are food-grade pellets which are extremely safe to add to your well. I use the pellets myself, because they are cleaner to deal with and they are food-grade. The pellets are actually designed to be used in an automatic chlorination system that many people add to their wells. This system tracks your amount of water usage and adds just the right amount of chlorine year-round. Unfortunately they also cost $700+, so I do not have one.

Instead, I drop the pellets into the well by hand. Your well should have a small cap on the top of it that you can unscrew (mine is made of PVC). Just take the cap off and drop the correct number of pellets in, then replace the cap. It’s best to do this at a time when you are not going to be using your water for a few hours, so that the chlorine has sufficient time to do it’s work in the well.

Determining how much chlorine to use: If your well water is already funky, you are going to have to add high amounts of chlorine until you get the bacteria under control (your water starts looking better). Then, you will start reducing the chlorine amount. If your water is currently clean but you are worried about future contamination, just add 1 or 2 pellets per day and test the chlorine level in your water, and adjust accordingly. I use swimming pool test strips to get a rough idea of my chlorine situation…

Testing for chlorine amount with test strips: There are a lot of test kits sold at hardware stores for testing pool and hot-tub water. What you are looking for are test strips that measure ‘free chlorine’. NOTE: If the kit says ‘total chlorine’ or ‘combined chlorine’, it is NOT what you want. It has to test for ‘free chlorine’. Free chlorine is that which has not killed any bacteria. Combined chlorine is that which has already killed bacteria and has been rendered inert. When you first start adding chlorine to your funky water, you will add large amounts of chlorine (10 pellets per day) and still your test kit will reveal NO free chlorine. That is because all of the chlorine you are adding is becoming ‘combined’ with bacteria (used up).

Over time, as you keep adding chlorine, you will finally get control of the bacteria and your test strips will start to change color indicating that you have some free chlorine. Be very careful that your free chlorine does not become excessive. Remember that the test strips are made for measuring pool and hot-tub water, your well water should not have anywhere near that amount of chlorine in it. So you are just looking for the slightest change in color on the test strips. You want between 0.1 and 1.0 ppm (parts per million) of free chlorine to insure protection from the bacteria. If you go higher than 1.0 for any length of time, you risk disturbing the bacteria balance in your septic system.

Septic system issues: After my water clears up and I get my chlorine usage under control, I always add a dose of Rid-X to the septic system to help restore the balance (note that I do not regularly add rid-x and have been advised that large amounts of it do more harm than good, but it’s great for restoring balance after using a lot of chlorine).

How I handle it: If my water gets really bad, I will add 10 pellets per day until the cold water starts to clear up, then I will begin to back off. Through the whole process I will be testing my cold water with test strips at a sink to make sure I am not over-chlorinating. Once things are looking good, I will use 2 pellets per day until the middle of June. After that, the danger is usually over until next spring, so I will back off to 1 or 2 pellets per week just to keep the water clean and tasting nice. Then, around mid-March of the next year, I increase my dose to 2 pellets per day again. Note that I always seem to err on the side of using too little chlorine, and thus I have only had 1 year where I didn’t get a bacteria problem. This is usually because the spring snowstorms can make it very difficult to get to my well, thus I skip days. I wish I could afford one of those auto-chlorinators!

Re-infection: If I find that my well keeps getting re-infected despite several attempts to treat it, I will run a garden hose to the well from the house (yes this is a very long hose for me, but I just string together several cheap-o hardware store hoses). Then I will shock treat the well by adding about 40 pellets. Wait about 1.5 hours for the pellets to dissolve (you can use liquid bleach if you are in a hurry). Then turn on the water hose and start circulating it through the well. Wait for the hose water to have a noticeable chlorine odor to it, then aim the hose all around so that it washes down the insides of the well casing. The high amount of chlorine in the water will sterilize the well components. It’s best if you water your lawn with some of the well water after this because the high amount of chlorine could cause septic system problems, but it will not harm your grass if you use a spray nozzle (the nozzle aerates the chlorine rendering it harmless). After the chlorine smell has been reduced, you can stop watering your lawn (remember this is illegal in some counties so be careful!) and just monitor your level with test strips and add Rid-X to your septic tank if necessary.

Critical safety tip: Remember that there is electricity AND water down there! As you are washing down the well, do not touch anything metal! Do not let the rubber hose get wet on the outside. Be very careful not to do anything that could conduct electricity to your body. Wear rubber gloves for an extra level of protection. The well motor will be turning on and off during this time, and you could be killed by an electrocution if you are not extremely careful. Personally, I never touch any metal part of the well casing without first turning off the circuit breakers to the well.

Now for your hot water: During this process of treating your well, you pretty much have to ignore your hot water, because it is a separate issue that poses it’s own problems. First, concentrate on getting your well clean, then you will have an easier time fixing your hot water.

Hot water heaters contain an ‘anode rod’. The anode rod is designed to attract all corrosion to itself, thus preventing your water heater from corroding. In fact, nearly every time a water heater fails, it is because the anode rod wore out a year before and caused the tank to start corroding. Would you like your water heater to last forever? Then check and replace your anode rod every few years! Anyway, when the sulfur-eating bacteria enter your hot water tank, they form an electro-chemical reaction with the anode rod that makes them reproduce like crazy! This is why it is very difficult to remove the bacteria from your hot water. You have to use much higher levels of chlorine than you had to use with your well. This is difficult to do, how do you get the chlorine in there? I will cover that problem below.

First, let’s take a look at the anode rod. Water heaters come with a magnesium anode. Sulfur-eating bacteria prefer this material, so you do not want it in your tank! Shut the water off going into the water heater, then remove the anode (you will see it, it is a large plug on the top of the water heater. Remove that plug and pull out the anode, it will be several feet long. Go to a plumbing supply store (Home Dept and Lowes usually do not stock these) and purchase an ALUMINUM anode to replace it. The bacteria do not like the aluminum rod as much, making it easier to get the problem under control.

Now, this is where we talk about adding chlorine to the tank. You need to install a heat-proof valve (no plastic of any type!) in the top of your water heater so that you can open it and dump chlorine directly into the tank. I solved this problem at the same time I purchased my anode rod. My new aluminum anode rod could either be capped on top, or it could have a fitting attached to the top of it. I attached a heat-proof brass valve to it. So, when I need to add chlorine, I just shut off the water to the tank, open up a hot water faucet and/or open the tank’s relief valve to drain some water, open my new valve on top of the anode rod, and dump some chlorine in there. It’s best to not use any hot water for the next few hours so the chlorine has a chance to do it’s work. Adhere to the same rules as above about testing and not over-chlorinating your septic system, and in a few days both the sulfur smell and the chlorine smell should disappear from your hot water.

Note that this information is based on my own experience. You may have other problems with your water, such as a leak that is attracting dirt, or iron bacteria. Also, the amount of chlorine you need to use may be different than mine because of differences in well-depth and static water level, that’s why it’s so important to test. But for most of us who live in the high-country in a sulfur-rich environment, the above information will keep our water clean and healthy.