Three reasons you should chlorinate your well water.

Posted by David Cannon on 15th Apr 2017

I often get asked questions about adding chlorine to well water. I have found that there are three reasons or problems that require the addition of chlorine bleach to well water.

1. Iron Control

2. Hydrogen Sulfide Control (Rotten egg smell in water)

2. Bacteria Control

Iron Control: Iron is found in ground water more often than not. In cases where there is an extremely high presence of  solubilized iron many issues will start to develop. The most common complaint is stained fixtures and iron stains on clothing. in extreme cases plugging can occur reducing water flow. When the soluble iron contacts oxygen it will change from a soluble state to an insoluble form of iron or what is better known as rust. These rust deposits develop rather quickly as soon as water comes out of the ground. To treat this problem we need to introduce an oxidizer to cause the soluble iron to form a rust particle before it exits the pipe and trap these particles in a contact tank or on the surface of a filter. Any oxidizer will do. Oxidizers can be: Air, Hydrogen Peroxide or in this case chlorine or chlorine bleach. When the iron is oxidized and forms a rust particle the new particle becomes large enough to be trapped in a filter. 

Hydrogen Sulfide Control: Just like iron hydrogen sulfide is found in many ground water systems and is more of a nuisance causing water to smell like rotten eggs. Nobody want their water to stink! Adding chlorine to a system is a simple way to oxidize the hydrogen sulfide causing it to combine with other H2S molecules. These particles become large enough to be caught in a filter and easily removed. A little bleach goes a long way. 

Bacteria Control: If you water tests positive for harmful bacteria you will need to continuously disinfect the water. Many disinfectants can be used however chlorine bleach is the easiest to find. You can get bleach anywhere. The most common test is a fecal coliform test. Yes it's exactly what is sounds like 'Fecal Matter'. This test is easy to perform by a lab and is used as an indicator for other forms of harmful bacteria. Chlorination of drinking water is a recognized method by all health departments. Regular testing must be done if you find this in your water. 

How to effectively chlorinate your water for the above symptoms:

Often I hear stories about people pouring bleach down wells or dropping chlorine tablets down the well. This is simply a bad idea. For one you cannot get good control over chemical dosage and will certainly over or under dose the system. It's not effective for ongoing control. If you overdose the well it's likely you will damage your pump and put people at risk. Don't do it. There's a better way! 

We recommend using a chemical metering pump to add small amounts of chlorine to the well. When I say small amounts I really mean it. You only need a small amount of chlorine to control iron, hydrogen sulfide and bacteria. The effective dosage will vary depending on how much of each contaminant is present in your water so mixtures will vary. 

The objective is to add only enough chlorine to get the job done. As chlorine reacts with the contaminated water it will be absorbed by the reaction. You want to feed enough chlorine to fully react with the contaminants and have just enough left in the water that can be tested with a chlorine test kit. You will need to adjust your dosage until you see a small amount of free chlorine in your water but not more than is recommended. If you have too much chlorine in the water you can actually re-dissolve the iron or hydrogen sulfide and it will pass through your filter. 

Free chlorine level should be in a range of 0.5 PPM to 1.0 PPM. Anything higher than 1 PPM will be heavily chlorinated and smell like a swimming pool. Chlorine residuals above 2.0 PPM is considered unsafe for drinking. 

Equipment needed to chlorinate your water: 

  1. Chemical pump
  2. Tank for mixing chlorine
  3. Free chlorine test kit

For most wells, you will only need a chemical pump that activates whenever the well is recharging the pressure tank. To do this you will connect the chemical pumps power cord to the same circuit that turns on the well pump. Wire the pump in parallel to your well circuit. Every time the well turns on you will be adding a a set amount of chlorine. Inject the chlorine before the pressure tank just after the check valve near your well head. 

If you well has a variable speed pump you will need to add some extra equipment to ensure chemicals are added proportional to the flow rate. You will need a water meter with a sensor that outputs pulses that are used to control the chemical pump. Some pumps have built in circuitry that can accept a pulse input. If you pump does not have this feature you can use a device called a 'Pump Control Module' that accepts the pulses from a water meter and turn on the pump for a few seconds each time a pulse is received. This is also common when feeding chlorine into a system after the pressure tank. 

Once the chemical pump has been connected to the system, test with plain water for leaks you can begin adding chlorine to your tank and start the process of adjusting your system. Start out with an extremely week solution of chlorine and water. We want to make small adjustments to the mixture while measure for free chlorine at the lat fixture in the system. If you test shows little or no chlorine residual you will need to make the mixture a little stronger. This may take a little trial and error but it's worth it. Remember you only want enough to get the job done with a little extra left over. About .5 PPM free chlorine is ideal. Try not to do all of your adjustments with the pump. It's always better to adjust the mixture and just leave your pump at 100% output. Pumps work much better this way and you limit ware and tare on the pump. At this point you should see your water problems go away. 

If you don't like the idea of using chlorine in the water you can consider using hydrogen peroxide. Hydrogen peroxide is not easy to find and it's very dangerous to handle in concentrated form so if you go this route please contact us to discuss the proper handling and safety when using it. The benefits of hydrogen sulfide are great. It's tasteless and odorless and does not generate chlorinated by-products. It has a very fast oxidation reaction. You can buy it from a special chemical supplier. Many dairy farms are using this over chlorine so you might call one in your area and find out who they buy from. 

Chlorine is neutralized by carbon filtration so if you want to remove the residual chlorine from your water after it's done its job consider adding a carbon filter to the system.