Maine Advanced Enviro-Septic and Enviro-Septic Design & Installation Manual Changes 2019 Edition


Presby Environmental (PEI) was recently acquired by Infiltrator Water Technologies (IWT), uniting PEI’s market-leading combined treatment and dispersal technology with IWT’s broad offering of onsite wastewater treatment system technologies. PEI’s pipe-based combined treatment and dispersal products have a nearly 30-year history of demonstrated wastewater treatment performance, with third-party testing organizations including NSF, MASSTC, and BNQ documenting the excellent passive wastewater treatment performance of the AES and other combined treatment and dispersal systems.  IWT has been manufacturing drainfield, septic tank, and tank-based wastewater treatment products for over 30 years.

Specifications change

IWT and PEI are confident about the long-term treatment performance of PEI’s wastewater treatment and dispersal systems that are already installed. However, the companies have elected to modify certain design and installation specifications in order to standardize requirements for the merged companies’ combined treatment and dispersal product offerings nationwide. The specifications change will also increase factor of safety relative to long-term hydraulic performance of AES systems.

What changed?

Changes are limited to product offerings, sizing, vertical profile, and replacement provisions, as follows:

  • Removed Simple-Septic® as a current design option.
  • Decreased the system sand cover requirement from 6 inches to 3 inches minimum as a result of recent performance testing. This decreases the system height from 24 inches to 21 inches.
  • Increased pipe requirements to a minimum of 70 ft./bedroom for residential applications and 2.14 GPD/ft for commercial applications. Pipe requirements that exceeded these minimums have not been changed.
  • Included the ability to substitute AES pipe for “in-kind” replacement, expansion, or repair of existing Enviro-Septic® or Simple-Septic systems®.
  • Instituted various formatting changes that do not affect system design and construction.

When are these changes taking effect?

The new manual has been approved by the state and can now be used for all designs. Designs submitted after September 1, 2019, must be in accordance with the new manual.

Where can I get a 2019 edition manual?

You can get a copy of the 2019 edition manual here. You can also call us, your Maine Distributor at Septic Systems of Maine (SSoME) (207) 782-1620 and request a copy be mailed to you.

What about the online training?

The online certification training videos have been updated to reflect the 2019 manual updates. If you are already certified, you are not required to re-certify in order to continue designing and installing PEI systems.

Will there be seminars offered to discuss the changes?

PEI and IWT will be hosting two Maine seminars, the first will be Thursday, July 25th at the PEI Headquarters in Whitefield, NH as part of the Motorcycle Lunch & Learn coordinated by Brent Lawson. The next will be in the evening on Thursday, August 8th at the Augusta Civic Center (76 Community Drive, Augusta, ME 04333), which will accommodate 150 attendees. This will provide an opportunity to learn about the changes, ask questions, and to introduce you to other IWT products. Click here to register for one or both of these events.

How can I ask questions? Call us at SSoME (207) 782-1620 or PEI/IWT directly (800) 473-5298 or email us at