Underground Water Deposit

We are in the process of buying a rural property near Llanos de los Olleres that currently has an underground water deposit as the only supply of water. The property has stood empty for almost a year so we would like to get the deposit drained, flushed out & then refilled with fresh water. Can anyone recommend a reliable company to carry out this work ? 

On a separate note, we've been told that the water main runs nearby & the property could be connected to it. Again, any recommendations for this work would be appreciated. 

Thanks,

Tim & Dawn