A household installs a septic tank for excreta disposal in a village dependent on shallow dug wells for drinking water. According to standard siting recommendations, the minimum horizontal distance between the septic tank and any well should be:
- A 6 metres
- B 10 metres
- C 15 metres ✓
- D 30 metres
Correct answer: C. 15 metres
Explanation
A septic tank should be sited at least 6 metres from the dwelling and at least 15 metres from any well to prevent groundwater contamination by effluent percolation. Six metres is the house clearance distance, not the well clearance, and is the tempting distractor. Groundwater flow direction must also be considered, since a well downstream of a septic tank remains at risk even beyond nominal distances.
Reference: Park's Textbook of Preventive and Social Medicine, 27th ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
Written and medically reviewed by the StethoPrep medical team.