How to choose a water well drilling rig
Most rig-buying mistakes come from starting with the machine instead of the hole. Work through depth, geology, diameter and access in that order, and the right rig class picks itself.
Start with the water, not the rig
Ask neighbours, local drillers or the water authority two numbers: how deep nearby wells are, and how deep the water sits in the dry season. Your target depth is the depth of a good producing zone, not the first water you touch.
Then add margin. A common rule of thumb is to choose a rig rated 30–50% deeper than your target: a 120 m target well points to a 180 m class rig. Ratings assume favorable ground; margin is what lets you finish the wells that turn out deeper or harder than planned.
Let geology pick the drilling method
| Ground | Method that works | Why |
|---|---|---|
| Clay, sand, soft shale | Mud rotary | Mud carries cuttings out and holds the hole open in loose ground |
| Granite, basalt, hard limestone | DTH (air hammer) | The hammer fractures rock at the bit; mud rotary grinds slowly and wears bits |
| Mixed or unknown formations | Combination rig | Switch between mud and air as the formation changes |
If you do not know the geology, that is an argument for a combination rig, not for guessing. Our method comparison goes deeper: mud rotary vs DTH drilling.
Diameter follows the job
- Domestic and livestock wells: typically 4.5–6 in holes — enough for standard submersible pumps.
- Irrigation wells: typically 8–12 in, to fit larger pumps and higher flow.
- Municipal and industrial wells: 12 in and up, set by the pump and casing program.
Check the rig's diameter range against your casing program, not just the open-hole size — the hole must clear the casing you plan to set.
Match the carrier to your ground and your calendar
- Trailer-mounted (e.g. Aquilon 180T): tows behind a pickup; best when jobs are road-served and spread out.
- Crawler (e.g. Aquilon 300E, Aquilon 450C): walks over rough, wet or sloping ground; slower between distant jobs.
- Electric drive: quiet, low running cost where grid or generator power is available — a real advantage near homes and livestock.
Budget for the whole system
The rig is the biggest line, not the only one. A working budget also covers drill rods and bits for your depth, a mud pump or an air compressor sized to the method, casing, freight to your site, and a starter set of wear parts. A quote that includes shipping — as ours do — is much easier to compare than a factory-gate price.
Common questions
How much depth margin should I buy?
Rate the rig 30–50% deeper than your deepest planned well. Ratings are set in favorable ground; margin absorbs deeper aquifers, harder formations and the wells you have not planned yet.
Can one rig drill both mud and air?
Yes — combination rigs run mud rotary in soft ground and a DTH hammer in rock. If your geology varies between jobs, a combination rig such as the Aquilon 450C avoids owning two machines.
What do you need from me for an accurate quote?
Target depth and hole diameter, the ground you expect (soil, rock, mixed), power available on site, and the delivery address. With those five, we quote the rig and shipping together.
Is an electric rig powerful enough for farm wells?
For wells in its depth class, yes. The Aquilon 300E drills to 1,000 ft (300 m) on grid or generator power, quietly — the limit is depth class, not the drive type.
Related: compare all rigs · drilling applications · how shipping is quoted
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Tell us the job and the location. We quote equipment and shipping together.