Very unusual to only be charged for first 100 mtrs, and to make a guarantee of supply, they won't know that till they hit water, maybe check translation (diarios is daily) .
Normal procedure company sends a water diviner who finds water and an estimate of depth, surprisingly accurately, supplies a quote, normally a clause that says no water and also for an independent third party to check and confirm water pressure is sufficient, insufficient pressure, no water, no payment.
Equally might be a clause that says if they find water you pay for depth drilled, which might be more than estimated.
You should have someone on hand checking drilled depth
Get independent quotes for pump and electrical work.
Water should be analysed after silt etc settled (local blood analysis clinics also do water)
You must get a Licence from Camra before work commences
Can any of you guys recommend a company that digs boreholes.
We have had an estimate and it came out over 6000 euros.
Our borehole was cleaned but it has possibly collapsed due to being an old metal liner that's about 20 years old.
The new pump keeps stopping as there is sand in the water that is seizing it up and tripping the fuse board, the pump is at about 116 meters deep. the borehole total depth is a bout 140 meters.