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{{procontable | pro=
- Removes over 98.5% bacteria, 100% bacteria, turbidity, some iron, manganese, arsenic. Quality of water improves with time. <br>
- Cheap, no on-going costs<br>
- High flow rate – upto 36 liters per hour. <br>
- Water looks and tastes good. <br>
- Maintenance is easy <br>
- Cement can be easily acquired in most developing countries. <br>
- Household labour or volunteer labour can be utilized in the manufacturing process <br>
- The concrete container is heavy durable and durablerobust. It does not need to be replaced as often as a plastic container <br>
- The spout piping is located inside the filter. Consequently, it is less prone to damage than a plastic filter, which has piping on its exterior <br>
- Fabricated from local materials. Plastic fabrication usually requires the importation of raw material or the finished product. Depending on your views of international trade, this can be an advantage or disadvantage. <br>
- The life expectancy of a plastic model is substantially less than a concrete model. The ultimate disposal of plastic is a concern for the environment <br>
- Encouraging and empowering local people to completely manage their own project increases local sustainability and motivates others to take action for safer water. This process can only be facilitated if the product supply is managed locally. In most cases, if a plastic model is used, there will always be a dependence on outside manufacturers and distributors to supply filters at a higher cost. <br>
| con=
- Biological layer takes 3 weeks to develop to maturity <br>
- High turbidity (> 100 NTU) will cause filter to clog and require more maintenance <br>
- Requires that the filter be used periodically on a regular basis <br>
- Cannot remove color or dissolved compounds (same as all other filters)<br>
- Can be difficult to move (weigh 170 lbs / 77 kgs)<br>
}}
==History and social context==
Concrete filters are heavy (70 – 75 kg for thin wall version and 135 kg for heavy wall version). Poor transportation of filters can lead to cracking and/or breakage. Filters should not be moved after installation.
Maintenance is required when the flow rate drops to a level that is inadequate for the household use. Swirl and dump maintenance for Continued use of the filter causes the pore openings between the sand grains to become clogged with debris. As a result, the flow rate of water through the filter decreases. To clean the filter, the top layer surface of the sand is simplemust be agitated, takes thereby suspending captured material in the standing layer of water. The dirty water can then be easily removed using a few minutes and small container. The process can be done by household usersrepeated as many times as necessary to regain the desired flow rate. The frequency of This procedure is sometimes call a "swirl and dump " maintenance practice. The need to do this depends on turbidity the amount and quality of inlet waterbeing put through the filter. If the water is relatively clean (turbidity less than 30 NTU), the filter can likely run for several months without this maintenance procedure. The outlet, lid and diffuser should be cleaned on a regular basis.
The outlet should also be cleaned regularly using soap and water or a chlorine solution.
After cleaning, a re-establishment of the biological layer takes place, quickly returning removal efficiency to its previous level.
====Manufacturing====