There are numerous brands of portable water tanks that include different shapes, as well. A bladder or pillow tank is square or rectangular-shaped and lies flat on the ground, then rises to look like a "bed pillow" with added water. An onion tank looks like a flexible cup full of water with the top of the tank showing water exposed.
Below are a few commercial tanks to choose from, although note that there are many, many brands available as these are just a few. Below these commercial tanks is information on onion tanks.
==Aero Tec Laboratories==
F: +31 (0)541 760499<br>
==Onion tanks==
[[Image:onion tank.jpg|thumb|right|200px|An onion tank. Photo: Seventh Framework Programme]]
Flexible, self-supporting tank intended for the storage, chlorination and distribution of drinking water, as well as for the treatment of turbid water by (assisted) sedimentation.
{| border="1" cellpadding="5" cellspacing="0" align="none"
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! width="50%" style="background:#efefef;" | Advantages
! style="background:#ffdead;" | Disadvantages
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| valign="top" | Can be used for all water treatment processes, easy to set up transport and pack. <br>
| valign="top" | Durability, cost, fragile. Can easily role over if not on truly leveled ground. Children love them!<br>
|}
==Other water tank links==
* International Federation of Red Cross and Red Crescent Societies (ICRC) - water tanks available: [http://procurement.ifrc.org/catalogue/overview.aspx?volume=1&groupcode=114&familycode=114003 Emergency items catalog]
