Typical residential septic tanks range in size between 750 gallons ... but they are also made of fiberglass and polyethylene and are not subject to cracking while underground.

Plastic septic tank prices range from $500 to $2,500 ... a real estate agent and owner of Bramlett Residential Realty in Austin, Texas. “There are so many factors that go into septic ...

According to him, plastic septic tanks are usually bought by people ... “If you are building a residential house, you may construct a septic tank of 10 feet deep and 10 feet wide,” he says.