Well Shock Chlorination Dosage Calculator
Estimate the standing water volume in your well casing and the bleach dosage needed for shock disinfection.
50500+
Standing Water Volume
220 gallons
8.25% Unscented Bleach Needed
45 fl oz (1.4 qt)
Safety first: work outdoors or with the wellhead cover open, wear gloves and eye protection, and never mix bleach with any other cleaning chemical. Run every faucet in the house until you smell chlorine, then let the system sit for at least 12 hours before flushing the lines outdoors (away from septic systems and vegetation) until the chlorine smell is gone. If contamination persists after shock treatment, have your water professionally retested and consult a licensed well contractor.
Read the Bacteria Treatment Guide
This is a planning estimate using standard published shock chlorination guidance, not a substitute for professional well disinfection service, especially for wells with a history of repeated bacterial contamination.
What You Need for Shock Treatment
- Unscented 8.25% bleach. Regular household bleach, not scented or splash-less formulas. Use the amount from the calculator above.
- Post-treatment bacteria test. Retest 7 to 14 days after flushing. A certified lab test is the most reliable; a home coliform test kit is a quick screen. Compare well water test kits
- Rubber gloves and eye protection. Shock-strength chlorine irritates skin and eyes.
Related Diagnosis & Treatment Guides
- Does shocking a well fix it for good?Why a shock is a reset, not a cure, plus septic safety and when to drink.
- Positive coliform test: what it meansWhen a shock treatment is the right first step, and when it is not enough.
- Rotten egg smell in well waterSulfate-reducing bacteria in the well are one cause that shocking can knock back.
- Iron in well water and iron bacteriaOrange slime and swampy odors point to iron bacteria, which chlorine controls.
- Black slime on faucets and toilet tanksOften bacteria feeding on manganese or iron.
- Choosing a whole house well water filtration systemPermanent protection after the shock: UV, filtration and the right order.