Field glossary

DFU

Drainage fixture unit, a dimensionless load value for a fixture used to size drains and vents; one DFU is about 7.5 gallons per minute of discharge

Used across 3 Anvilfield field guides, most in Plumbing.

Also defined as

Drainage fixture unit, the dimensionless load value that sizes drains and wet vents; a full bathroom group runs about 5 DFU
Drainage fixture unit, the load currency that sizes the sewer against the code table

Where this shows up