Electricity and water is usually charged based on the meter, gas is usually charged at a fixed price per person per week/month, or it is agreed that you simply buy a new bottle of gas once the old one is empty. No worries, the home owner will help you with that! 

Electricity costs on average about €0.22/KwH (prices can vary a bit depending on the provider). This is a bit more expensive than in The UK, about the same as in The Netherlands, and cheaper than in Germany. Water costs on average about €2.80 per m3, prices vary per county and per month (heavier use is more expensive per m3). Water is in general more expensive than in the north of Europe.

Remember that in a warmer climate you will save on heating, so very likely you will spend less on these consumables than you would at home.