By Adam Chubbuck, Team Leader, Team Alpha Charlie of Douglas Realty. Retired U.S. Navy Chief. Licensed in Maryland and Virginia.
A large share of Anne Arundel County is not on public water and sewer. Davidsonville, Crownsville, much of south county, parts of Pasadena and the Broadneck peninsula, and scattered pockets everywhere else run on private wells and on-site septic systems.
Buyers moving here from a city or from out of state routinely underestimate what that means. It is not a defect and it is not something to avoid. Plenty of the best property in this county is on well and septic. But it changes your inspection scope, your future renovation options, and occasionally your entire purchase decision, and almost none of that is visible in a listing photo.
This is what I walk my buyers through before they write an offer on a well and septic property.
The Single Most Important Thing: Septic Systems Are Sized by Bedroom Count
Start here, because this is where the expensive surprises live.
An on-site septic system is permitted and sized for a specific number of bedrooms. That permitted bedroom count is a legal capacity limit, and it does not always match what the listing says.
I have seen four bedroom listings on three bedroom septic permits. Sometimes it is an honest mistake where a previous owner finished a basement room and started calling it a bedroom. Sometimes it is a bonus room over the garage. Either way, the permitted capacity is what governs.
Why it matters practically:
- Your lender and appraiser may treat the property as having the permitted bedroom count rather than the marketed count, which affects value.
- If you ever want to add a bedroom, you need system capacity to support it, and that may not be available.
- If the system fails and needs replacement, it gets replaced at permitted capacity unless you can qualify for more.
What to do: ask for the septic permit early. The Anne Arundel County Department of Health’s Sanitary Engineering Program maintains these records and can be reached at 410-222-7193. Compare the permitted bedroom count to the listing before you get emotionally committed.
Your Inspection Scope Is Bigger Than Standard
A standard home inspection does not cover the well or the septic system. Those are separate inspections by separate specialists, and you need both.
The septic inspection
At minimum this should include locating the tank and lid, pumping and inspecting the tank interior, checking baffles, evaluating the distribution box, and assessing the drainfield for evidence of failure such as surfacing effluent, saturated ground, or unusually lush vegetation over the field.
Ask the inspector directly: how old is this system, and what is its remaining useful life? Conventional systems do not last forever, and a system at end of life is a five figure problem.
The well inspection and water testing
Two separate things and you want both.
Mechanical inspection covers the pump, pressure tank, well cap and seal, and flow rate. Flow rate matters practically. A well that produces adequately for one person may not support a family of five with two showers running.
Water quality testing is where Anne Arundel County has some specific local considerations. Standard testing covers bacteria and nitrates. In this county you should also discuss testing for radium, which is a documented concern in portions of the county. The Department of Health operates an assistance program that specifically covers radium water treatment systems alongside septic and private well assistance, which tells you the issue is real enough to warrant a program.
The county has also conducted targeted well testing investigations in specific areas, including published results for wells on Summerfield Road in Gambrills. If you are buying in an area with any history of groundwater concern, ask about it directly rather than assuming.
Do not skip water testing to save a few hundred dollars. It is the cheapest insurance in the entire transaction.
What You Can and Cannot Do Later
This is the section buyers wish they had read before closing rather than after.
Adding living space
If you want to increase the habitable area of a home on septic, the county requires that the existing system be evaluated for its adequacy to handle both existing and proposed flow. You do not simply pull a building permit and start framing.
The limited home addition provision
Anne Arundel County does provide a path. If the Department of Health determines the existing septic system is functioning properly, a limited home addition may be possible by adding an advanced pretreatment unit to the existing system.
The parameters, per the county:
- Up to a 50 percent increase in the living space of the existing dwelling
- Capped at a 1,000 square foot addition
- No increase in the number of bedrooms
Requirements for approval are addressed in the Anne Arundel County Water and Sewer Master Plan. If your plan for a property involves a significant addition, verify feasibility with the Department of Health before you close, not after.
Pools, sheds, garages, decks, and patios
These require a county building permit and are approvable provided minimum setback requirements can be met. Setbacks from the well, the septic tank, and the drainfield all constrain where you can put things. The county publishes a Distance Requirement Chart for this.
The practical consequence: that back corner where you pictured the pool may be sitting on your reserve drainfield area. Check before you buy if it matters to you.
If the Property Is Undeveloped or You Are Buying Land
Perc testing is the gate, and the process is more involved than most buyers expect.
The basics. Percolation testing determines the size and type of septic system that can be installed on a specific lot. Applications go through the Bureau of Environmental Health at 410-222-7193, and the county lists a $450.00 application fee for sites requiring perc testing.
A minimum of three satisfactory perc tests are generally required to establish a sewage disposal area, and the Department of Health may require additional tests based on soil consistency, topography, landscape position, and the size of the proposed system.
You need room for three systems, not one. Perc tests must be performed in adequate numbers to represent areas for an initial system and two replacement systems. Adequate land must be set aside for those future replacements. This is the requirement that surprises people most, and it can meaningfully limit what you can build.
Slopes and neighboring wells reduce your usable area. Depending on the site evaluation results, you may have to reduce the size of the house and the size of the septic system to meet requirements. In cases of adverse soil or groundwater conditions, a property may only be developable when public sewer becomes available, which may be never.
Wet season testing is a real scheduling constraint
Properties in areas with certain soils and high water tables must be tested during wet season, which normally runs February 1 through April 30, because the highest water table is typically experienced in February, March, and April. Wet season testing exists so that a system is not evaluated during conditions that flatter it.
The season is set using a network of monitoring wells that measure actual groundwater levels, and it moves. In 2026 the county announced on January 23 that the start of wet season testing would be delayed due to low groundwater levels while applications continued to be accepted on a first come, first served basis, and then announced on April 15, 2026 that it had stopped scheduling perc tests for the season. Applications for other testing that year had to be received by April 3, 2026.
What this means for you: if you are buying land with a contingency on perc results, understand that the testing window may not accommodate your timeline. Build that into your contract dates rather than discovering it in March.
Also note: test results are mailed to the property owner and applicant. Department representatives will not release results in the field at the completion of testing. Do not expect an answer the day of.
If the Property Is Near the Water
Two additional layers apply, and both are significant.
Before filing a perc application for a property located within 1,000 feet of a waterway or within the Chesapeake Bay Critical Area, the county directs applicants to contact the Anne Arundel County Department of Planning and Zoning at 410-222-7463.
State approved Best Available Technology (BAT) nitrogen-reducing units are required on all new septic system installations within the Chesapeake Bay Critical Area. These cost meaningfully more than a conventional system to install and they carry ongoing maintenance obligations. If you are buying waterfront or near waterfront land, price this in from the beginning.
Your site plan submission also has to show more than you might expect: property lines, building restriction lines, proposed house location and size, neighboring wells and septic systems within 100 feet of the property, Critical Area lines where applicable, and any proposed or existing improvements including pools, sheds, garages, decks, driveways, patios, and porches.
I cover the Critical Area rules in depth in a separate article, because for waterfront buyers they deserve their own treatment.
The Ongoing Ownership Reality
Nobody tells buyers this part, so here it is plainly.
Septic maintenance. Plan on pumping every few years depending on tank size and household load. Keep the records, because they are worth real money when you sell. A seller who can produce a decade of pump receipts is in a materially stronger negotiating position than one who cannot.
What not to put down the drain. Grease, wipes labeled flushable, harsh chemicals in volume, and anything else that disrupts the biology of the tank. Garbage disposals and septic systems have a complicated relationship.
Well maintenance. Test water annually at minimum. Know where your well head is and protect it. Understand that a pump failure means no water at all until it is fixed, which is a different experience than a municipal outage.
Advanced treatment units, if you have one, carry a service contract and periodic inspection requirements. Budget for them.
Financial assistance exists. The Anne Arundel County Department of Health provides financial assistance for some environmental programs, including an Application for Assistance covering septic systems, private wells, and radium water treatment systems. Worth investigating if you are facing a major repair.
What This Means When You Are Negotiating
Well and septic conditions are legitimate negotiating leverage, and they are also legitimate reasons to walk.
Order the inspections early in your contingency period, not at the end. Septic and well specialists have limited availability in this county and a delay can push you past your deadline.
A failing system is a real number. Replacement costs vary enormously with system type, site conditions, and whether BAT is required, so get an actual quote rather than a guess before you decide how to handle it.
Get the permit record. Bedroom count, installation date, and any repair history. This is public information and it is worth the phone call.
Sellers, read this too. If you are selling on well and septic, get your inspection and water testing done before you list rather than during the buyer’s contingency period. Prepared sellers do not lose deals to a surprise septic result three days before the deadline, and a clean pre-listing report removes the single largest source of buyer anxiety in this category.
How My Team Handles These
Well and septic properties are a routine part of working this county, and the difference between a good outcome and a bad one is almost always sequencing. Ordering the right inspections early, pulling the permit record before the offer rather than after, and knowing which questions to ask the Department of Health.
I have closed more than 350 homes across this corridor over the past five years and I run Enclave Property Management out of Pasadena, so I see these systems from the ownership and maintenance side as well as the transaction side. That perspective matters here, because the question is not just whether the system works today. It is what it will cost you over the next fifteen years.
If you are looking at a well and septic property and want a straight read on it, reach out to Team Alpha Charlie of Douglas Realty. If you are further back in the process, current Anne Arundel County home prices by submarket and the free Anne Arundel County home valuation are reasonable starting points.
Anne Arundel County Well and Septic FAQ
Does a standard home inspection cover the septic system?
No. Septic and well inspections are separate, performed by separate specialists, and both should be ordered in addition to your general home inspection. Water quality testing is separate again from the well’s mechanical inspection.
How many bedrooms can I have on a septic system in Anne Arundel County?
Whatever your septic permit allows. Systems are sized and permitted for a specific bedroom count, and that permitted count governs regardless of what a listing advertises. Pull the permit record from the Anne Arundel County Department of Health’s Sanitary Engineering Program at 410-222-7193 before you write an offer.
Can I add an addition to a house on septic in Anne Arundel County?
Possibly, with conditions. When habitable area increases, the existing system must be evaluated for adequacy. The county provides a limited home addition path where, if the Department of Health finds the existing system functioning properly, an addition may be approved with an advanced pretreatment unit added. That path allows up to a 50 percent increase in living space, capped at a 1,000 square foot addition, with no increase in bedroom count.
When is perc testing done in Anne Arundel County?
Properties in wet season restricted areas must be tested during wet season, normally February 1 through April 30, when the water table is highest. The exact season is set using a network of monitoring wells and it shifts year to year. In 2026 the county delayed the start due to low groundwater levels and concluded scheduling on April 15. Applications go through the Bureau of Environmental Health at 410-222-7193, and the county lists a $450.00 fee for sites requiring perc testing.
How many perc tests do I need to build on a lot?
Generally a minimum of three satisfactory tests to establish a sewage disposal area, with additional tests possible at the Department of Health’s discretion based on soil, topography, landscape position, and system size. Critically, testing must cover enough area for an initial system plus two future replacement systems, and land must be set aside for those replacements.
Do I need a special septic system near the water in Anne Arundel County?
Yes. State approved Best Available Technology nitrogen-reducing units are required on all new septic installations within the Chesapeake Bay Critical Area. Additionally, before filing a perc application for property within 1,000 feet of a waterway or within the Critical Area, the county directs applicants to contact Planning and Zoning at 410-222-7463 first.
Should I test well water for anything beyond bacteria?
Discuss radium with your testing provider. It is a documented concern in portions of Anne Arundel County, significant enough that the Department of Health operates an assistance program specifically covering radium water treatment systems. Standard bacteria and nitrate testing is the baseline, not the ceiling.
Sources and Dates
Regulatory information above is drawn from published guidance of the Anne Arundel County Department of Health, Bureau of Environmental Health and Sanitary Engineering Program, and Anne Arundel County Government Inspections and Permits, including perc testing procedures, well and septic applications for property improvements, and 2026 wet season testing announcements dated January 23, 2026 and April 15, 2026. Best Available Technology and Critical Area septic requirements reflect Anne Arundel County Department of Health published procedures. Limited home addition parameters reference the Anne Arundel County Water and Sewer Master Plan as cited by the Department of Health. Fees, seasons, procedures, and requirements change. Verify all of it directly with the Anne Arundel County Department of Health at 410-222-7193 and Planning and Zoning at 410-222-7463 for your specific property. This article is general information and not legal, engineering, or environmental advice.
Let’s Talk About Your Move
If you are considering a well and septic property in Anne Arundel County, the smartest thing you can do is get the permit record and the right inspections lined up before your contingency clock starts running. Send me the address and I will tell you what to order, what to ask for, and what the answers actually mean.
I am Adam Chubbuck, Team Leader of Team Alpha Charlie of Douglas Realty. I am a retired U.S. Navy Chief, a licensed Real Estate agent in Maryland and Virginia, and I have closed more than 350 homes over the past five years across the Baltimore to Annapolis corridor. My team serves buyers and sellers throughout Anne Arundel County, Howard County, Baltimore County, Baltimore City, and the surrounding markets, with deep experience supporting military, veteran, and Department of Defense families. I also run Enclave Property Management out of Pasadena, Maryland, so I see this market from the ownership side as well as the sales side.
If you are weighing a move, start with a real conversation and real numbers. Reach me directly at 443-347-6692, email [email protected], or start at TACMD.com.
Adam Chubbuck
Team Leader, Team Alpha Charlie of Douglas Realty
Douglas Realty | Licensed in MD and VA
443-347-6692 | [email protected] | TACMD.com
Smile more,
Adam Chubbuck
