__NOTOC__<small-title />[[Image:Storage_tank_for_rooftop_harvesting_icon.png|right|80px]][[Image:brickcement.jpg|thumb|right|300px200px|A brick-cement tank before the application of the cement. Photo: Arrakis and Connect International - [http://www.arrakis.nl/reports/Manual_Fabricating_Brick_Cement_Tanks_short_03_lr.pdf Fabricating Brick Cement Tanks.]]]
Brick cement tanks are a low cost option for storing water gained through water harvesting. In general it is cheaper than ferro-cement tanks and easier to build. In clay areas, be sure to build the tank robustly enough to resist cracking. Ground tanks should always be designed as either hemispherical (half ball shape) or cylindrical because those shapes equalize the pressure of water and soil whether the tanks are full or empty (square or rectangular tanks will always crack).<br>
Water extraction can be done using gravity, [[Handpumps]] or other pumps, or with a bucket.
===Suitable conditions===
* The area should be suitable for [[rooftop rainwater harvesting]]. Volumes can be 0.5 to 30 m3.
* Tanks should not be located near a pit latrine/toilet or rubbish or on an anthill.
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! width="50%" style="background:#efefef;" | Advantages
! style="background:#ffdeadf0f8ff;" | Disadvantages
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| valign="top" | - Cheaper and easier to build than ferro-cement tanks <br>
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===Resilience to changes in the environment===
====Drought====
For more information on drought: [[Resilient WASH systems in drought-prone areas]]
===Construction, operations and maintenance===
'''General advice on cement''': A common cause of cracks in structures and linings (e.g. in tanks, dams, waterways, wells) is errors in mixing and applying the cement. First of all, it is important that only pure ingredients are used: clean water, clean sand, clean rocks. The materials have to be mixed very thoroughly. Secondly, the amount of water during mixing needs to minimal: the concrete or cement needs to be just workable, on the dry side even, and not fluid. Thirdly, it is essential that during curing the cement or concrete is kept moist at all times, for at least a week. Structures should be covered with plastic, large leaves or other materials during the curing period, and kept wet regularly.
'''Specific advice''':
[[Image:Brick cement tank.PNG|thumb|right|300px200px|Construction of a small brick cement tank, Mozambique. Materials consist of (local produced) bricks (or blocks of hard rock), cement and steel wire. Approximately 1 bag of 50 kg cement per m3 tank volume. The bigger the volume of the tank, the lower the amount of materials (and thus costs) per m3 tank volume. Photo: Arrakis and Connect International - [http://www.arrakis.nl/reports/Manual_Fabricating_Brick_Cement_Tanks_short_03_lr.pdf Fabricating Brick Cement Tanks.]]]
Brick cement tanks are constructed by placing an upright ring of bricks in a circle, with 3 rings of steel wire tightened around them. If the tank diameter is bigger than 2 meters more rings are needed. A second, third and fourth ring of bricks are added and suitably tightened. Make sure the wrapping of the barbed wire, g 12.5, is tightly around the outer side of the tank in a spiral spaced 5 cm at the lower half of the tank, where the greatest strength is needed, and 10 cm on the upper half. Cement is then applied on the inside and outside of the brick walls and to cover the bottom. A metal or PVC outlet pipe can be installed at the bottom. Once the cement has been applied, the tank needs to be covered with paper or plastic and kept wet for 7 days to cure the cement. Another curing option is to fill it up after the second day of installation.
* Physical inspection and repairing cracks with cement is also needed.
===Costs===[[Image:BrickTank.jpg|thumb|right|300px200px|This hemispherical tank built of burnt bricks reinforced with barbed wire and chicken mesh is for roof catchment of domestic water. [http://www.infonet-biovision.org/default/ct/180/soilConservation Infonet-biovison: Water storage.]]]
The cost of underground tanks can be high and variable in cost per m3 of storage (seem to average around US$30-40 per m3 of storage), sometimes a lot more depending on various factors.
* In Sri Lanka, brick tanks cost 28 per m3 of storage (5m3 tank cost $140).
===Field experiences===
* Brick cement tanks have been constructed in Nicaragua and Ghana, among other countries.
* [http://en.howtopedia.org/wiki/How_to_Build_an_Underground_Brick_Dome_Water_Tank How to Build an Underground Brick Dome Water Tank.] Case study in Sri Lanka.
===Manuals, videos, and links===
{{#ev:youtube|KinpClgH-IE|200|right|How to build a big tank}}
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===Acknowledgements===
* CARE Nederland, Desk Study: [[Resilient WASH systems in drought-prone areas]]. October 2010.
* [http://www.google.com/url?sa=t&rct=j&q=&esrc=s&source=web&cd=2&ved=0CEMQFjAB&url=http%3A%2F%2Fwww.paceproject.net/UserFiles/File/Water/Brick%2FUserFiles%2FFile%2FWater%2FBrick%2520tanks20tanks%2520for20for%2520storage20storage.pdf&ei=gJiHT63GKOaTiAKHtumMAg&usg=AFQjCNGVc0tObum9_8rPucTLz3eBkHXKNA&sig2=gYfzDMudwCrQ-VNQDP_HiA Brick tanks for rainwater storage]. Action Sheet 22. PACE and SEARNET Rainwater Harvesting Technologies.