Is my tap water okay to use?
It really depends on the region you live in as tap water quality will vary locally. If it taste/smells nice then its probably fine to use. Adding 1/2 a crushed campden tablet / 25 litres of water will remove any chlorine from the water which can help improve taste.
Alternatively most supermarkets offer own brand bottled water in 5 litre containers at a very reasonable price.