Which factors must be known before laying out a new OSSF?

The most comprehensive answer involves understanding that all the listed factors—water table level, building location and size of the property, and soil drainage capacity—are essential when laying out a new On-Site Sewage Facility (OSSF).

Knowing the water table level is crucial because it influences the placement of the system. If the water table is too high, it could potentially lead to system failure as the effluent can’t drain properly, causing pollution or backups.

The building location and size of the property are fundamentally important because they determine the layout and design of the OSSF. The system needs to be appropriately sized and located to function efficiently without causing any environmental issues or system failure.

Soil drainage capacity is vital as well, since the efficacy of an OSSF depends on how well the soil can absorb and filter the effluent. If the soil does not have adequate drainage capabilities, it could result in ponding or saturation, negatively affecting the performance of the OSSF.

Thus, all these factors are interconnected, and neglecting any of them can lead to problems in the function and legality of the system. Therefore, the best answer is indeed that all of the mentioned factors must be known before laying out a new OSSF.