I think I have now found a suitable bungalow for my forthcoming long stay visit to Lamai. The owners are quoting Electricity = 6 ฿ / 1 unit , water = 20.-฿/1 unit. Is this the going rate for a rented property?

governement price for electricity is 3.3 baht per unit(depends how much you use), in my case i use 500 per month. in thailand the more you use, the higher the price per unit.

water is more than often free but some owners might ask 200 baht per month.

i never saw a house owner ask to pay water per unit, maybe this owner is a foreigner and thinks this is europe here?w

The owner is getting you to pay for is electric and water

Ask for the bills to be given to you and you pay them. if he refuses he is scamming you. As said water is around the 7 baht a unit and electric is as said 3 odd baht a unit. Look elsewhere if he refuses. Unless you are happy paying his bills as well ?

As Dunc has said....also go easy on the air con or the bill will double or treble or.....!

6 baht is a considerable markup, last place i stayed I paid 5 baht but they had diesel generators for any outage (and they're were a few couple of hours) so I didnt think too much of it. Water price seems fair enough. If no super infrastrucutre for the electric (everything earthed and generators) then Id say 4.5/4 baht max.