Sewer vs Septic Cost Calculator

Access this webpage from a desktop or laptop computer to use the Calculator below. Default values represent averages for West Acton homeowners, where available. Note that the default setting for the number of years until septic failure, 25, is just an example setting. Most homeowners in West Acton will not need to replace their septic system in the next 30 years [link].

Use the sliders below the plot to specify input paramters. You can return to the defaults at any time by reloading the page. For a discussion, see the cost comparison article.


Amount I spend annually to pump/maintain my system: 




I expect my septic system to last:



Expected system replacement cost (avg: $30,000):



I would pay for septic replacement:

Septic/home equity/home improvement loan APR:

       (if septic replacement not paid up-front)



I would pay the sewer betterment fee:

Betterment APR (if betterment fee not paid up-front):



Expected sewer hook-up cost:


Household water usage (avg: 120 gal/day):



I would hook up to the sewer:

My house would use:



1.  The Acton Board of Health states that septic systems should be pumped every two years. The default $170 is the annual cost to pump a 1500-gallon tank ($340) averaged over two years. The corresponding annual cost for 1000 gallons is $70 per year. For 2000 gallons, $220 per year [source: ABC Cesspool].

2.  Maintained systems have an expected life of 60 to 80 years. Therefore at most one replacement event is expected to occur in the time span of the plot.

3.  The cost of septic system replacement in Acton ranges from $18,000 to $50,000 with an average cost of $30,000 [ABC Cesspool, G. Nichols Construction]. Note that the $30,000 average includes system design ($3,000 - $5,000), installation ($25,000) and permit ($1000).

4.  Final betterment fee APR not yet announced by the Town.

5.  Average residential water usage in West Acton for the first quarter of 2019 [source: Acton Water District].

6.  See the proposed route to find out if your property would be on gravity or low-pressure sewer. Most properties would use gravity sewer. However, properties on Mass Ave between Villageworks and the High School, as well as some properties on Arlington Street, would use low-pressure. See a discussion of low-pressure here. The cost of grinder pump replacement ranges from $2000 to $4000 (replacement E-1 unit) and is approximated here as $3000 every 8.5 years. [source: Matt Dalton, SES Wastewater]

7.  Formula used for loan payment calculations is here.

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