Test pits (observation holes)

• Two test pits (observation holes) excavated to a minimum depth of 1.2 metres, or to refusal (where you cannot dig further), whichever is shallower.

– The appropriate number of test pits will depend on the size of the drainfield area and the variability of soil conditions.

– The appropriate depth of the test pits is that which provides soil and water table information. This is a minimum of 0.9 m below the proposed infiltrative surface;

– Where auger holes are used, a minimum of two observation test pits should be excavated to confirm auger test results;

– Test pits should minimize the impact on dispersal and receiving areas from pits and machinery; and,

Soils profile

• A description of the soil profile, including the soil texture, structure, consistence (rupture resistance), colour, at the depth of the proposed infiltration surface;

• A description of key measured depths, including soil redoximorphic features (mottling and gleying), roots, and total depth of each pit.