15m3 plastic water tank can be produced just as vertical. There is no production as horizontal for plastic water tanks over 5m3. There is two colour options for plastic water tanks. One of is the white. And the other one is the blue. Blue tanks are more costly than white tanks. Plastic water tanks have advantages and disadvantages. The most important advantages of tanks are mass production and cheaper prices comparison with the other tank types. One of disadvantage of tanks is no production as horizontal over 5m3. And the other one is the unchangable dimensions. Plastic water tanks are produced by polythene raw material. Polythene is the thermo plastic and its resistance is high against to chemicals. You should ask to sales responsive for storage of liquids except of water. Plastic tanks are suitable for food.