Question: how much does it cost to install a 1250 gallon septic tank?
Answer: Most homeowners spend between $3,280 and $5,040 for a 1,250-gallon system that supports 3 or 4 bedrooms. Septic system installation with two alternating pumps costs $9,571 on average and can go up to $15,000. Your final cost depends on the conditions of current waste lines and the soil where the septic tank will go.