In Indiana, a flood dose system is required because:
1. The trenches are higher than the septic tank and so a dosing tank must be installed to lift the effluent to the trenches.
2. The field system is >1500 sq.ft. Indiana septic code 410 IAC 6-8.3 says that any absorption field greater than 1500 sq.ft. must be pump assisted (> 500 linear feet of 3′ wide trench)
Pumps used in ANY septic system application must be sized appropriately and must be an “effluent or sewage pump”.
Regular sump pumps are less expensive but will not hold up to the conditions in a septic dosing tank. At least not for long.