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How to Shock a Well

Posted on November 20, 2016

If you’re using a private water supply from your own well, it is important that you are taking steps to thoroughly clean the water prior to consuming it. Shock chlorination – ‘shocking’ a well – is the preferred method of initially treating a well to make the water safe to drink.

To help you decide whether the treatment is right for you, read on to find out more about the treatment and its benefits.

How does shock chlorination work?

Shock chlorination works by introducing a very strong chlorine solution to the water system, including the well, pump, distribution line and any other features your well may utilise. This is done on a one-time basis to kill, or ‘shock’ any bacteria that may be present in the water or growing inside the well or systems to ensure that, from that moment onwards, water extracted from the well will be clean.

Who could benefit from shock chlorination?

Many water sources could benefit from shock chlorination, including wells, springs, swimming pools and any other stagnant water that could harbour bacteria or algae. Shock chlorination is often recommended for circumstances such as:

  • If flooding water has contaminated the water source
  • When lab results show a bacteria presence
  • If there are high iron levels
  • A new well is built or repaired
  • If the distribution system has to be opened for repairs or maintenance

These are not the only instances when shock chlorination could be beneficial, so if you have any doubts as to the safety of your water source, contact a specialist for more advice.

Is it safe to shock a well?

It is very safe to shock a well, but only if the correct safety measures are carried out. Chlorine can be a very harmful substance that can be detrimental to the health of those in close proximity, so must be handled carefully.

Safety practices for a risk-free process:

  • Keep a large (upwards of five gallons) fresh water supply close by incase concentrated chlorine comes into contact with skin – use this water to clean the affected area.
  • Wear appropriate safety clothing and equipment such as goggles, rubber gloves, boots and overalls or an apron to protect your clothes.
  • Make sure the area is well ventilated.

It is also worth noting that the correct measures of chlorine must be used for the size of the water source, and too much chlorine can be toxic if ingested. We’ll look at the formula for working out the correct amount of chlorine later in this article.

Preparing for the treatment

Once you have the correct safety measures in place, you can begin to prepare for the treatment. The first thing that we’d recommend you do is look for and eliminate any potential sources of contamination. If you don’t do this, you run the risk of your well becoming quickly recontaminated after the shock treatment has been actioned, making it redundant and the water unusable.

If there are any components of your well system that you think may not withstand the harsh chemical process of shock chlorination unscathed, we’d recommend that you remove those components and sanitise them individually using a less abrasive method. There are many available, so either ask a specialist or browse online for suggestions.

The treatment

Chlorine should be used at a ratio of 200 milligrams per litre. To work out the correct amount of chlorine for your water supply, you will need to do a bit of maths. The information required can usually be provided by the company who installed the well, and the following equation can help you reach your sum:

Depth of water X gallons of water per foot = total gallons of water in the well.

Once you have completed the calculation to work out the total gallons of water in the well, you need to account for the additional water in the system components, which again should be known by the installers or manufacturers of the components. As well as this, you should add 50 gallons for the pipeline. Hot water heaters and pressure tanks should also be accounted for, if installed.

Once you have worked out the correct amount of chlorine to introduce into your system, you can begin the process:

  • Mix the chlorine with a few gallons of fresh water and pour the solution into the well. While doing so, attempt to run the solution down the walls of the well as much as possible to disinfect these areas.
  • Next, use a hose pipe to run water into the well; this will assist in mixing the chlorine into the well water. Alternate between mixing the chlorine and letting it stand until you notice a strong chlorine smell.
  • Open each faucet attached to the water distribution system to flush the appliances and taps until you begin to notice the chlorine smell at each faucet, at which point you can close the valve. If the chlorine smell is not transmitting to each outlet, add more chlorine to the well a bit at a time and try again.
  • Do not use the well for a minimum of two or three hours, but preferably overnight. This allows the system to be thoroughly disinfected.
  • Run every faucet until the chlorine smell has completely gone and the system has been flushed. If you have a septic tank attached, you will need to intercept the wastewater through hose pipes or buckets and dispose of the water on a gravel area free of plants.

Take a water sample 1-2 weeks after this process to test for bacterial contamination. Do not drink the water from the well during this time, and wait until the results confirm the water is safe to ingest before doing so.

For a constant supply of clean, drinkable water, get in touch with Wildon UK to find out more about our water tank chlorination and disinfection services. We can restore stagnant, corroded or contaminated water supplies back into fresh and safe water in no time at all.

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