Water and electricity
Electricity and water are two items that can be prohibitively expensive and therefore essential to price into the amount you are paying for the site. The cost includes the standard utility connection fees plus any infrastructure that has to be built, e.g. a pole, both of which involve the network operator. For electricity ESB Networks in ROI, NIE in NI and for water Irish Water in ROI, NI Water in NI.
On your site, any work such as digging the trenches will be your responsibility and will usually come at the cost of hiring a groundworks tradesman to do this for you with a digger.
You will need water on site before you begin construction and, although not essential because generators can be used, an electricity supply will make life a lot easier during the build. Temporary connections may be worth considering but can represent an unnecessary cost. For example in ROI, a temporary builder’s connection comes with expensive commercial rates (cost per kWh higher than for domestic).