Assertion: septic tank | /r/HasProperty | pumped at measure scum
Facets:
value: normally
type: DEGREE
Source sentences:
text: at MEASURE SCUM & SLUDGE, the septic tank needs to be pumped when the floating scum layer has accumulated to reach 3 inches of the bottom of the outlet baffle or tee.
text: at MEASURE SCUM & SLUDGE, normally a septic tank should be pumped when the bottom layer of sludge is within 18 inches of the tank outlet.