Only noticed this hole last week, after a long hot, dry summer.
The Thais are just suggesting to fill it in with rocks and earth, but I'm wondering if there is more behind this?
 

Something has caused that sinkhole. More than likely you have a water leak. Dig around those water pipes and check. If they're  okay do what the locals tell you and backfill it using compaction..

Is it a ground well or a storage tank ? I think ground well and water leaching in has eroded the ground. Best fill with rocks and infill gaps with soil.

18 minutes ago, LivinginKata said:

water leaching in has eroded the ground.

Therefore that eroded soil as gone somewhere. If inside the well he may well need to clean it out.

Snake pit.....

6 hours ago, IvorBiggun2 said:

Therefore that eroded soil as gone somewhere. If inside the well he may well need to clean it out.

 Aways need clean out ground well every few years 

 

Would that mean surface water go straight into your well now, that won't be much clean...!?  (I thought surface water go through a few meters of earth will get cleaned up a bit..., not much, but some. I maybe wrong though...).