Deep well drilling in Bali

Siting comes from geology, not from a man with a bent rod. We look at known aquifer depths for your area, logs from nearby wells, the surface geology and the distance to septic systems and the coast, then drill where the water is likely to be and the contamination is not. Across much of the south the productive layers sit between 40 and 90 metres; on the limestone of the Bukit, 120 metres and beyond is ordinary.

Construction matters as much as depth. Casing to full depth, slotted screen positioned against the water-bearing layer rather than guessed at, graded gravel pack around it, and a grouted seal in the upper section so surface water and septic seepage cannot run down the outside of the casing. Then development, a step and constant-rate yield test with drawdown recorded in litres per second, and a laboratory analysis before anybody drinks anything.

Depth, yield and the limits of guessing

Depth here is a geography question. Shallow wells of 15 to 30 metres still work in parts of Tabanan and inland Gianyar, but across the built-up south that shallow water is both scarce and suspect — it is the layer the septic tanks share. Protected aquifers in Canggu, Seminyak and Kerobokan typically begin somewhere between 40 and 90 metres, while karstic limestone on the Bukit drains fast and holds its water deep, so 120 to 150 metres is a normal outcome rather than a bad one.

Yield is the number that decides your pump, and it has to be measured. We run a step test to find where drawdown accelerates, then a constant-rate test at the intended duty to see whether the level stabilises. A hole giving two litres per second for ten minutes and half that after four hours is not a two-litre well, and specifying a pump from the first figure is how wells get burned out in their first dry season.

Taking water responsibly

South Bali's groundwater is under genuine pressure. Abstraction has outpaced recharge across the tourist belt for years, water tables have dropped, and saline intrusion now shows up in coastal wells that were fresh a decade ago. Over-pumping your own well is self-defeating: pull harder than the aquifer delivers and you draw in salt or silt, and the water you end up with is worse than the water you had.

So we design to the tested yield rather than to a pump catalogue, recommend storage so the well refills between draws instead of running continuously, and pair wells with rainwater harvesting and recharge pits wherever the roof area allows — every cubic metre caught in January is a cubic metre not taken from the ground in September. Abstraction beyond modest domestic use needs a SIPA permit, and we prepare the drilling log, yield data and coordinates that application requires.