--- title: "Bay Restoration Fund Septic Grants in Anne Arundel | TBG" description: "When Anne Arundel County requires a nitrogen-reducing (BAT) septic system, how Bay Restoration Fund grants work, and adding bedrooms on septic." url: https://thebrettgroup.com/guides/septic-upgrades-bay-restoration-fund/ last_updated: 2026-10-13 --- [TBG](https://thebrettgroup.com/) / [Home Remodeling](https://thebrettgroup.com/remodeling/) / Septic guide Local guide · Anne Arundel County · October 2026 # Septic upgrades and Bay Restoration Fund grants in Anne Arundel County If your home is on septic, two things shape your project: whether a nitrogen-reducing (BAT) system is required, and whether the state's Bay Restoration Fund will pay for it. Here is how both work, and what it means for an addition. Get matched with a builder who knows this - **1,000 ft**: Within this of tidal water, new and replacement systems must be BAT - **100%**: Of the allowable BAT cost covered for households up to $300K income - **$60/yr**: Bay Restoration Fee on septic users - **$25,000**: Grant toward connecting a failing system to sewer **The short version:** inside the Chesapeake Bay Critical Area, every new or replacement septic system in Anne Arundel County must be a nitrogen-reducing "BAT" unit. Outside it, BAT is usually optional, except when an addition needs more capacity than your current system has. The state's Bay Restoration Fund can cover most or all of the cost, and the county's Health Department reviews any project that adds living space or bedrooms. ## 1. What a BAT system is BAT stands for Best Available Technology for removing nitrogen. It is a pretreatment unit installed in place of, or ahead of, a conventional septic tank, which cuts the nitrogen your system sends toward the Bay. The Maryland Department of the Environment keeps the list of approved units. ## 2. When BAT is required Under state rules, BAT is required for new construction and for **replacement systems in the Critical Area** (land within 1,000 feet of tidal water), and for very large systems. Maryland dropped the statewide requirement for new homes outside the Critical Area in 2016, and Anne Arundel County confirms that new and replacement systems outside the Critical Area are not required to use BAT. The county exception: if your existing system can't handle the extra living area of an addition, a BAT unit is required **inside or outside** the Critical Area. ## 3. Bay Restoration Fund grants Septic users pay a **$60 a year** Bay Restoration Fee, and that fund pays for upgrades. In Anne Arundel County, grants go in priority order: failing systems in the Critical Area first, then failing systems elsewhere, then systems with no permit record, then working conventional systems (Critical Area first each time). Funding is first-come, first-served and there may be a waitlist. | Household | Grant toward the BAT upgrade | | --- | --- | | Income up to $300,000 | 100% of the maximum allowable cost | | Income over $300,000 | 50% | | New construction on a vacant lot | Reduced by $1,200 | Low- and moderate-income owners may also get help replacing the drainfield. You still pay permit fees (the county lists a $450 percolation test application fee and a $625 installation permit fee), any work beyond the unit, and anything above the grant. Apply through the Health Department's Sanitary Engineering Program (410-222-7324 for the grant program) and use a contractor from its pre-qualified list. ## 4. The ongoing cost: maintenance A BAT unit must be operated and maintained for its whole life by a certified service provider, with at least one inspection a year. New units come with a two-year maintenance contract and warranty; after that, you need to keep a service contract in place. Budget for it. ## 5. Adding on or adding bedrooms On a septic lot, the building permit goes to the Health Department, and you list existing and proposed bedrooms and square footage. The system must be sized for the larger home, and the lot must have room for **two future replacement systems**. If a conventional system can't be expanded but your current one works, the county allows a one-time limited addition: up to 50% more living space, capped at 1,000 square feet, with an advanced pretreatment unit and **no added bedrooms**. Check this before you design a bedroom suite. ## 6. Septic to sewer If public sewer runs along your property and your system is failing, a Bay Restoration Fund grant of up to **$25,000** can help pay to connect. The county's long-term *Our wAAter* septic-to-sewer program aims to convert thousands of systems in dense waterfront neighborhoods over 30 years, with neighborhood petition projects paid back through an annual assessment. Check your address with the county before you replace a system that may soon be on sewer. ## Where this comes up most [Shady Side →](https://thebrettgroup.com/remodeling/shady-side/) · [Deale →](https://thebrettgroup.com/remodeling/deale/) · [Davidsonville →](https://thebrettgroup.com/remodeling/davidsonville/) · [Crownsville →](https://thebrettgroup.com/remodeling/crownsville/) · [Riva →](https://thebrettgroup.com/remodeling/riva/) · [Edgewater →](https://thebrettgroup.com/remodeling/edgewater/) ## Projects we match - [Additions](https://thebrettgroup.com/remodeling/additions/anne-arundel/): Bump-outs, second stories and in-law suites. - [New custom homes](https://thebrettgroup.com/remodeling/custom-homes/anne-arundel/): Build on your lot with a registered Maryland home builder. - [Bathroom remodels](https://thebrettgroup.com/remodeling/bathroom/anne-arundel/): Primary baths, hall baths and accessibility upgrades. ## Common questions ### Do I need a BAT septic system in Anne Arundel County? Yes for new and replacement systems inside the Critical Area (within 1,000 feet of tidal water). Outside it, BAT is generally not required, unless your existing system cannot handle the added living area of an addition. ### How much does the Bay Restoration Fund pay? For households with income up to $300,000, the grant covers 100% of the maximum allowable cost of the BAT upgrade; above $300,000 it covers 50%. You still pay permit fees, extra work and any cost above the grant. ### Can I add a bedroom if I am on septic? Only if the system is sized for the added bedroom and the lot has room for two future replacement systems. The county's one-time limited addition option does not allow added bedrooms. ### Who maintains a BAT unit? You do, through a certified service provider, with at least one inspection a year for the life of the system. New units include a two-year service contract. ### Is there help to connect to public sewer? If your system is failing and sewer is next to your property, a Bay Restoration Fund grant can pay up to $25,000 toward the connection. ## Official sources [MDE: Bay Restoration Fund BAT units](https://mde.maryland.gov/programs/water/bayrestorationfund/onsitedisposalsystems/pages/brf_bat.aspx) · [COMAR 26.04.02.07](https://regs.maryland.gov/us/md/exec/comar/26.04.02.07) · [MDE: Bay Restoration Fund FAQs](https://mde.maryland.gov/programs/Water/BayRestorationFund/Pages/faqs.aspx) · [AA County Health: BRF grants](https://www.aahealth.org/node/213) · [AA County Health: BAT upgrades](https://www.aahealth.org/node/212) · [AA County Health: building permits on septic](https://www.aahealth.org/node/209) · [AA County: Our wAAter septic-to-sewer](https://www.aacounty.org/node/2700) This guide is general information, not legal or engineering advice. Rules and maps change; confirm the requirements for your property with the permit office before you design or sign a contract. ## More local guides [Renovating or adding on in a flood zone in Anne Arundel County](https://thebrettgroup.com/guides/flood-zone-renovation-anne-arundel/) · [Building or adding on near the water: the Critical Area explained](https://thebrettgroup.com/guides/building-near-the-water-critical-area/) · [Remodeling ideas for Anne Arundel County's most common house types](https://thebrettgroup.com/guides/remodeling-anne-arundel-house-types/) · [Materials that hold up near the Chesapeake](https://thebrettgroup.com/guides/chesapeake-coastal-building-materials/) · [Deck permits in Anne Arundel County](https://thebrettgroup.com/guides/deck-permits-anne-arundel/) · [In-law suites and accessory dwelling units in Anne Arundel County](https://thebrettgroup.com/guides/in-law-suites-adu-anne-arundel/) · [Energy rebates for Maryland home remodels in 2026](https://thebrettgroup.com/guides/energy-rebates-maryland-remodel/) · [Renovating a home in the Annapolis historic district](https://thebrettgroup.com/guides/annapolis-historic-district-renovation/) · [Remodeling permits in Anne Arundel County and Annapolis](https://thebrettgroup.com/guides/permits-anne-arundel-annapolis/) · [How to hire a home improvement contractor in Maryland](https://thebrettgroup.com/guides/hiring-a-contractor-maryland/)