Testing your well water for bacteria

by | Aug 9, 2022

Testing your well water for bacteria can be a good thing if you drink the water.  But there are some things you should know before you embark on this journey.  Not everything is at seems so let’s dive into the issues.

You can have your water tested at a local testing laboratory.  Typically, you will collect the sample and then take that sample in to the lab.  The fees range from $0 to $50 depending upon the lab.  To do this properly, you first need to pick up a sample bottle from the lab.  You don’t want to use your own bottle as the sample bottles are sterile and they contain a pill that will deactivate chlorine up to 5 ppm.  That pill is made of Sodium Thiosulfate.  Don’t worry, that won’t be on the test.

When you are ready to take the sample, here is the process you will need to use.  If you don’t do this 100% right, the results will be wrong, and you wasted your time and money.  Trust me, this is not the time to do it good enough.  Do it right, or don’t bother with it.  First you need to choose where to get your sample.  If you have any water treatment that kills bacteria (like a chlorinator or a UV Light) you should take the sample before these items.  Theoretically, if you do have bacteria in your water, these devices will kill the bacteria so the test should always be negative.  So, if you have one of them on your water system, then you likely need to go to the pressure tank to get your sample.   Things like filters and water softeners won’t affect this test.  Even Reverse Osmosis units will not affect bacteria.  But it is always best to get as close to the source as possible.

 Once you have identified your source of water you need to sanitize everything.  Wash your hands with soapy water.   Wash the outside of the bottle.  Wash the outside of the faucet.  Wash the inside of the faucet.  You can use a flame to burn the tip of the faucet to kill any bacteria that might still be present.  You can get a cup of soapy water and try to push soapy water up into the faucet.  Then turn on the water and let it flow for at least 2 minutes.  Have the faucet on a slow flow so that you can control the filling of the bottle. 

Ok, this is the critical part.  Do it right or don’t bother.  If you are outside, make sure it is not raining.  If it is, just wait until it is not.  While the faucet is running, rinse of the outside of the bottle, the faucet, and your hands.  Hold your breath.  Unscrew the lid.  Don’t set the lid down or let it touch anything.  Quickly fill the bottle.  Don’t wash out the little pill inside.  Don’t over fill the bottle.  Screw the lid back on.  Now you can breathe.  Turn off the water.   Put the bottle on ice and run it straight to the lab.

You should get your results in 24-48 hours depending upon the lab.  If you manage to get a clean sample to the lab your first time, you should be proud.  That is a rare thing.  Most people get a few false positives until they learn to take each step seriously.  The lab can test for many things but in the area of bacteria, they are looking for two things.  Coliform and E-coli. 

Coliform is a type of bacteria that exists pretty much everywhere.  It lives in your digestive tract and in soils.  Luckily, you can ingest as much of this stuff as you want, and it won’t hurt you.  But if you’re your well has coliform, it is an indicator that it is possible for more harmful bacteria to get into your water.  Basically, if water can quickly get into your well after contacting the soil, then it could wash in some really bad stuff that might actually hurt you.   In the Central Texas area where we have deep wells, finding coliform is not common.  We get a lot of false positives from sampling errors. 

E-coli is the bad bacteria that we are all trying to avoid.  It can cause some major health issues and if your well water legitimately has E-coli, you need to contact your local well professional or governmental agency to determine what steps can be taken to prevent this.  Your well might be too close a septic system or might not be sealed properly.  This is a very rare occurrence in our area and most positive test results are sampling errors. 

After seeing how hard it is to get a sample without bacteria, you might be considering how hard it is to drink anything that doesn’t have bacteria.  And you would be right.  That glass that was washed and sat on the shelf for an hour.  It has bacteria in it before you touch it.  So, you might be thinking what you can do about it.  There are two basic ways to kill the bacteria in your water.  Chlorine and UV light.

You can set up a chlorine injection system that pumps a small amount of chlorine into your water so it will kill any bacteria that is alive.  The chlorine needs 30 minutes of contact time to make sure the water is safe to drink.  This can be achieved with large “kill tanks” that allows the water and chlorine time to mix before they flow into your house or by using a storage tank.

But if you don’t like injecting chlorine into your water, another solution is to use a UV light.  This is a tube that your water flows through that has a UV light bulb inside.  The light kills the bacteria without adding any chemicals to your water.  There is no tank needed on this system as the light kills immediately. 

Now that I have sufficiently freaked you out about bacteria, its time to go wash your hands.  If you have any questions, we are here to help.