Chlorine is an effective and important disinfectant used to remove harmful bacteria and viruses from water. The shock chlorination technique is adopted to clean well water when it becomes contaminated due to flood runoff or after fixing a crack in the well. In this type of disinfection, large amounts of chlorine are circulated through the well and pumped through the well’s pipes into the plumbing, faucets, and fixtures in your home. The amount of chlorine used during shock chlorination of wells is much higher than the levels normally used to disinfect tap water, so it is not safe to drink this water.
So in such cases, people usually ask how long it will take to remove chlorine from well water and when you can safely consume the chlorinated water. You have to read this guide till the end to get your answers. 
How Long Does Chlorine Will Take to Leave Your Plumbing System After Shock Chlorination?
It takes 30 minutes to 24 hours to start the shock chlorination process and remove all the chlorine from the well, circulating through it. After the chlorine is circulating through the well, the flushing process begins. It takes an hour to a day for all the chlorine to leave the well. The large difference in time is due to the many differences (mainly depth) between each well. A very shallow well can be flushed in as little as 30 minutes, while a deep well can take up to 24 hours.
During shock chlorination, chlorine is also passed through your home’s plumbing system. Most plumbers turn each fixture and faucet on until the chlorinated water is drained and then turn them off to maintain chlorine contact with that part of the system. Once the well is free of chlorine odor and the proper contact time has passed, open all faucets throughout the house and let the water run until the chlorine odor is gone.
This process should only take a few minutes if done correctly. Sometimes, hot water taps need to run much longer than cold water taps. You may also need to drain the water heater.
When Can You Safely Consume the Chlorinated Water?
Well water is generally safe to drink within 30 minutes to 24 hours after shock chlorination. However, it is recommended to wait at least 24 hours for all chlorine to be drained from the plumbing system or for the smell of chlorine to dissipate completely. Check all faucets and showers to ensure the chemical smell is gone, including outside faucets and garden hoses.
The safe chlorine level in water is too low to smell. So if the water still smells, you know it’s not drinkable yet. If you are sensitive to chlorine, avoid taking long showers, wear rubber gloves, and rinse your dishes for few days after the shock chlorination process.
Safe Limits of Chlorine in Drinking Water
The best way to determine if shock-chlorinated water is safe to drink is to purchase chlorine test strips and test the water. These are available at hardware stores and online.
According to the Environmental Protection Agency, the maximum contamination level for chlorine is 4 mg/l. Most chlorine test strips measure chlorine in ppm. Ideally, the test should record 0.3 to 0.5 ppm of chlorine in the water. We recommend running this test multiple times on different faucets in your home to ensure that the concentrated chlorine solution is completely drained from your plumbing system. When the water test finally indicates that your drinking water has safe chlorine levels, you can start consuming it. 
Final Thoughts
If you have to shock chlorinate your well water, you must wait for at least 24 hours before starting to consume it. It depends on the type and depth of your well that how much time is required to remove chlorine from the well water. Shallow wells will take 30 minutes, while deep wells will take 24 hours to remove chlorine from the water.
Frequently Asked Questions
1. How long does chlorination of a well last?
Some chlorine may remain in the system for 7-10 days. It is recommended to drink slightly chlorinated water because of its health benefits. If you notice an unpleasant taste or odor, run the water while the chlorine dissipates.
2. How often should well water be shocked?
If you own a private well, it’s a good idea to test the water a few years in advance if you find contaminants such as bacteria. If these tests show positive results for bacteria, chlorine disinfection may be a good option.
3. When can you take shower after your water is shock chlorinated?
Take shower for at least 24 hours after shock chlorination of the well. Wait for an extra day or two has great benefits. Chlorine levels in wells only decrease when switching from chlorinated water to fresh water. This process usually takes 1-2 days.
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