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Best-Available Technology


The Maryland Department of the Environment has approved new septic system regulations that will require that all new septic systems in the entire Chesapeake Bay Watershed have the so-called “Best-Available Technology” (B.A.T.).MontgomeryCounty is entirely within the Chesapeake Bay Watershed. These regulations will take effect for all new septic system permits issued effectiveJanuary 1, 2013. It will apply to all new homes, as well as septic system permits issued for the enlargement of existing homes. The only major exemption is for the repair or replacement of failing septic systems. These requirements apply to both residential and commercial properties; and apply to both private and public ownership.

These B.A.T. systems replace the standard septic tank and use more advanced technology to reduce the nitrogen component of the waste-water discharged to the drain-fields. Many of these devices are aerobic treatment systems that use electrically powered air blowers to stimulate the growth of aerobic bacteria in the treatment unit. These units will prolong the lifespan of most drain-field systems.

The regulations will also mandate that property owners have their systems routinely inspected and maintained by certified septic service providers. Under State guidelines, the supplier of the B.A.T. unit provides the first 5 years of inspections, thereafter the costs shift to the property owner.

The expected financial impact of these changes will include:

  1. An increase of approximately $13,000 to $15,000 to the cost of the upgrade of the septic system.
  2. The applicant will need to submit an engineered plan showing how the selected B.A.T. will be incorporated into the new septic system; and showing adequate detail to insure the completed installation meets all of the manufacturer’s requirements. Costs will vary depending upon the private engineer’s fees.
  3. The on-going use of electricity of approximately $50 to $200 per year.
  4. The yearly cost of inspection and maintenance, the cost of which will vary.

The State of Maryland (MDE) has indicated that Chesapeake Bay Restoration Funds (BRF) may be available for qualified applicants for new BAT installations. These funds are based upon a “sliding-scale” and can range from 25% to 100% of the costs associated with the BAT. Please contact the Well & Septic Section (240-777-6319) for additional details.