How To Get Rid Of Coliform In Well Water

So, you just tested your well water and found coliform bacteria. First thought: “Am I supposed to boil everything forever?” Don’t panic. Grab that coffee, take a breath, and let’s chat this out.

What even is coliform, and why should you care?

Coliform bacteria are like the canary in the coal mine for your water. They’re usually harmless themselves, but they wave a red flag saying, “Hey, something nasty might be getting in here!” Think of them as the nosy neighbor who brings in all the drama.

If you’ve got coliform, you’ve got a crack in your system somewhere. It could be a loose well cap, a cracked pipe, or even a friendly raccoon climbing on your wellhead. Rude. Your job now is to evict them and lock the door behind them.

Step one: Find where they’re sneaking in

Before you start dumping anything down your well, do a visual inspection. Walk around your well like a detective. Look for gaps, rust, or anything that says, “Bugs welcome here.”

Check the well cap—is it tight? Is there a screen? Is it above ground level? If you see cracks or mud pooling near the base, that’s a front-row ticket for bacteria. Fix those first, or you’re just flushing money down the drain. Literally.

Step two: Shock chlorination—the nuclear option (kinda)

Alright, time to get your hands dirty. Shock chlorination sounds scary, but it’s just pouring bleach down your well. No, not the fancy kind you sniff when doing laundry. Use unscented, household bleach (like Clorox, no additives).

How much? Roughly one quart of bleach for every 100 feet of well depth, but check your well logs. Pour it in, let the water run from the hose until you smell bleach, then let it sit for 12 to 24 hours. Yes, your water will smell like a swimming pool. That’s the point.

Bacteria In Well Water

After that, flush everything—hoses, faucets, the whole system—until the bleach smell is gone. Then retest your water. If the coliform is gone, you’re golden. If not, you’ve got a bigger problem, like a hidden crack or a bad well seal.

Step three: Install a permanent solution

Shocking is a band-aid, not a cure. To keep coliform out, you need hardware. A UV light system is a common fix. It zaps bacteria like a sci-fi movie. No chemicals, no weird taste. Just clean, glowing death rays for germs.

Another option is a chlorinator, which dribbles tiny amounts of bleach into your water continuously. Or a reverse osmosis system for drinking water. Pick your poison—pun intended.

But here’s the thing: UV systems require electricity. They also need sediment filters first, or the UV light gets blocked by dirt. Otherwise, you’re just shining a flashlight on a muddy puddle.

Step four: Test, test, and test again

After you fix stuff, do not trust the water until you test it. Wait a week or two, then send a sample to a certified lab. Not the home test strips from the hardware store—those are about as reliable as a weather app in a hurricane.

How to Treat and Eliminate Coliform Bacteria in Well Water

Test again three months later. Coliform can be sneaky. It might hide in a biofilm in your pipes and come back when you’re not looking. Treat it like a bad ex—keep checking the door.

If you still see coliform after two treatments, call a pro. Seriously. Don’t be a hero. A well contractor has tools you don’t, like cameras and pressure testers. They’ll find the crack you missed.

Bonus round: Preventative habits

Keep your wellhead clean. Don’t pile leaves, dirt, or snow near it. If you’re a gardener, don’t fertilize within 50 feet. Trust me, your plants don’t need that much love.

Test your water every year, even if it’s perfect. Bacteria don’t send warning texts. They just show up uninvited, like that one relative who brings casserole and gossip.

And hey, if you ever get frustrated, remember: thousands of people deal with this. You’re not alone. Your well can be clean again. You just have to be a little stubborn—and a little handy with a jug of bleach.