A Simple Low Cost DIY Chlorinator

CTI-8 Chlorinator

CTI has developed a device capable of disinfecting water in gravity-fed potable water systems. The device, called the CTI 8 Chlorinator is an inexpensive, low-maintenance, non-electrical, appropriate-technology apparatus. It is capable of delivering a controlled dosage of chlorine sufficient to inactivate most pathogens (disease-causing organisms) found in most rural potable water systems. The CTI 8 accomplishes disinfection by directing water flow over solid chlorine tablets in a simple configuration of PVC tubing. A CTI 8 chlorinator can be built and installed for around $100.00 US per unit. For a typical community of 200 people, monthly operational costs including chlorine can be expected to be between $5 and $10 US, depending on various factors such as temperature, level of contamination and quantity of water flow.

The chlorinator is constructed of 3-inch and 4-inch PVC pipe and fittings, and ¼-inch PVC plate. The CTI 8 can be built in a matter of hours using basic hand tools. It uses chlorine in the form of calcium hypochlorite or trichloro-s-triazinetrione tablets approximately 2 ½ inches / 6.35 cm in diameter.

The development of the CTI 8 involved three years of research and development, plus two years of field-testing in fifteen rural water systems in Nicaragua.


  • Designed for rural areas w/gravity fed water systems w/a flow rate between 2 and 20 gallons per minute.
  • Will treat water systems serving a population of approximately 100-1,000 people.
  • Requires a clean water source with little organic material.
  • Requires a closed system from the water source to the end user. Or with an open system, the system must have a functioning filtration system, sedimentation system, or both. (See MSSF water treatment plant design)
  • Turbidity levels should be less than 10 units
  • Disinfectant used: Chlorine tablets (Calcium hypochlorite or Trichloro-s-triazinetrione—It’s important to note that the tablets must be approved for human consumption)
  • Requires testing and record keeping, and regular monitoring by someone trained in its operation. Chlorine levels measured with an approved chlorine comparator at the holding tank and at least 1 other point in the distribution system. Measurements must be taken 3-4 times per week initially and at least 1 time per week ongoing.

CTI Evaluation Form: (Here are the questions you need to answer.)

Design Manual: (Detailed construction manual)

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2 Responses to A Simple Low Cost DIY Chlorinator

  1. Brandon Hoffman says:

    It looks like a very simple design, and allows for easy maintainance. How are you regulating contact time prior to the service line? How many people are currently using this service?

    • Bob says:

      Hi Brandon, this is something I came across while searching for simple, low cost ‘appropriate technology’ solutions — the best I’ve seen so far. I’m just filing it here for my own reference. I haven’t implemented it.

      “How are you regulating contact time prior to the service line?”

      I was planning to follow the instructions in the ‘Operation’ section (pp 13, 14) of the Construction Manual linked to above, i.e. by adjusting the bypass valve, and/or inserting spacers until I get the desired residual chlorine ppm. (I also just came back from the US with a free chlorine meter.)

      But I would very much appreciate your review & comment on the treatment plant we will be building soon. Details here: http://biorealis.com/OMV/deeptech/?p=758

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