Town water is generally not suitable for Hydroponics, if you are using bore water, spring water, dam water or rain water, you may have to check to see if this is suitable.

What problems could occur, is the salt content of the water, may be too high, the zinc content from metal (zincalume) tanks, could make it toxic for plants (even though it may be still safe for us to drink), as well as any number of chemicals, poisons or fertilisers, could be contaminating the water supply.  Please speak to a Hydroponic Company about the water supply if you are unsure.

The most important factor affesting water quality is the "hardness" or "softness" of the water. Hard water means that there is alot of dissolved mineral content, primarily calcium carbonate which usually shows up as scale on hot water pipes. Soft water is generally very pure or low in dissolved solids. Reverse Osmosis Filtered water would be considered a pure soft water.