MassDEP encourages the development of I/A technologies with performance superior to conventional systems. As of December 2003, approximately 2200 I/A systems were installed and operating in Massachusetts, and several hundred more are approved and installed each year. To ensure that the use of I/A systems will protect public health and the environment, MassDEP has a three-tiered approval process for new technologies: Piloting, Provisional Use, and General Use.

  • Recirculating sand filters and humus/composting toilets are certified for General Use, subject to certain conditions.
  • MassDEP has issued Piloting Approvals, Provisional Use Approvals, Certifications for General Use, and Remedial Use Approvals for nearly 50 I/A technologies.
  • New technologies are under review on an ongoing basis.
  • In addition, technologies which are designed to reduce nitrogen may also receive a Nitrogen Removal Credit. There are 15 I/A technologies currently approved for nitrogen reduction.

    Click here for a summary of technologies approved for use in Massachusetts and under review by MassDEP.

Once I/A technologies have been approved for use in Massachusetts, they still must be reviewed and approved for actual installation at a specific site. MassDEP and your local Board of Health share responsibility for this step. The installation approval process is different depending on the type of technology approval received from MassDEP. See I/A Systems for Repairs and New Construction.

Piloting: Piloting involves installation, field testing, and technical evaluation to demonstrate that the technology can function effectively under the physical and climatological conditions at the pilot sites and provide environmental protection equivalent to a conventional Title 5 system. Click here for approval letters for technologies approved for piloting.

  • MassDEP will accept technologies for piloting when available data on the technology shows that it is likely to be able to provide a level of environmental protection at least equivalent to a conventional Title 5 system.
  • Piloting of a particular I/A technology may be conducted either for new construction or in remedial situations. Up to 15 sites per technology may be piloted.
  • Piloting must be done for at least 18 months and result in a full technical reporting of results. Piloting generally is not intended to address long-term operation and maintenance, although the information gathered during piloting should be used to understand these issues.
  • When a technology completes pilot testing, MassDEP can allow the technology to proceed to the Provisional Use Approval stage, require additional piloting, or disapprove the system. Piloting is considered successful if at least 75% of the pilot sites performed at the expected level of treatment for at least 12 months.
  • Piloting systems that meet performance goals are allowed to remain in place long-term. For piloting systems that exhibit problems, adjustments to system design and operation are necessary. In extreme circumstances, the piloting system may need to be replaced. To date, no piloting system has had to be replaced.

Provisional Use: Provisional Use Approvals are intended to evaluate whether an I/A technology can provide environmental protection at least equivalent to a conventional system under actual field conditions in Massachusetts and with a broader range of uses than in the controlled environment of piloting. Click here for approval letters for technologies approved for provisional use.

  • Provisional Use Approval typically occurs after a technology has been piloted successfully or has been proved satisfactory past performance over at least two years of general usage in one or more states outside Massachusetts. A system approved for Provisional Use can be installed in remedial situations or for new construction where a system in compliance with Title 5 could be built.
  • Under Provisional Use Approval, a minimum of 50 systems must be installed and evaluated for at least three years.
  • The Provisional Use Approval stage evaluates operation, maintenance, and monitoring issues, and MassDEP uses the data to set final discharge standards and other conditions for General Use.
  • Provisional Use is considered successful if at least 90% of the installations have demonstrated over three years performance at least equivalent to a conventional Title 5 system.

Certification for General Use: When an I/A technology has successfully completed the Provisional Use stage, it receives Certification for General Use. I/A systems certified for General Use can be installed at any site where a conventional Title 5 system can be installed. Additional monitoring and reporting is generally not required, although MassDEP has the option of requiring monitoring as part of its Certification. Click here for approval letters for technologies certified for General Use.

MassDEP can determine that a technology certified for General Use may be used for new construction on lots that do not meet all of the requirements of Title 5 for installation of a conventional septic system. However, as of December 2003, no I/A technology had yet been certified for General Use for new construction on a lot that does not meet the required percolation rates, that does not have at least four feet of naturally occurring soil, or does not have the necessary separation from high groundwater.

Remedial Use Approval: MassDEP also approves I/A technologies for Remedial Use to improve conditions at existing sites served by a failing, failed, or nonconforming system. Click here for approval letters for technologies approved for Remedial Use.

Technology approvals for Remedial Use often include criteria under which a technology can be used, in order to allow one or more of the following:

  • Reduction in the size of a soil absorption system,
  • Reduction in the distance to groundwater, or
  • Reduction in the required depth of naturally-occurring pervious soils.

If designed in compliance with the applicable MassDEP approval letter for the technology, I/A systems proposed for Remedial Use do not require MassDEP approval. As with an application for a conventional Title 5 system, the local Board of Health must approve an alternative system before installation and issue a Disposal System Construction Permit.

Nitrogen Removal Credits: Many systems, as part of their approval process, apply to MassDEP for Nitrogen Removal Credits. Title 5 restricts design flow to 440 gpd per acre in areas designated as "nitrogen sensitive." These include the Zone II of public water supply wells, new residential construction served by both private wells and on-site systems, and other areas formally designated as nitrogen sensitive. Some I/A technologies are specifically designed to remove nitrogen from wastewater, and many of these systems seek a nitrogen removal credit, which allows the property owner to increase the design flow per acre, usually to either 550 or 660 gpd per acre from the standard 440 gpd per acre.

To date, 18 technologies have received nitrogen removal credit. Click here to see the list.

Remember: Once you have identified a MassDEP-approved I/A technology for installation, you must also have approval for its installation at a specific site. MassDEP and your local Board of Health share responsibility for this step. The installation approval process is different depending on the type of technology approval received from MassDEP. See I/A Systems for Repairs and New Construction.