How to Get a Septic Variance from Your Board of Health

By Buz Artiano, BuildX | October 2025

When we talk to people who are thinking about building an ADU, we hear this a lot. "My system works perfectly, but the town says I need a full replacement." The septic system that passed Title V inspection last year now all of a sudden has to have a $45,000 upgrade the second that you even mention adding an ADU to your property. It feels unfair, that's because a lot of time it is!

At BuildX, we have been through countless variance requests for ADUs in Massachusetts. We work with civil engineers who specialize in Title V compliance and Board of Health approvals. Our engineering partner, Kevin Grady of Grady Consulting, has turned in hundreds of variance requests in over 50 towns in Massachusetts. The relationship with the Board of Health really matters, and we've got the people and experience to make sure everything is able to move forward quickly.

The variance process can decide whether you need a simple $3,000 connection or a full $45,000 rebuild. We understand that this item alone can be the deciding factor in whether you can afford to build the ADU or not. The septic system is the wild card in the ADU process, and understanding how to request a variance helps gives you a bit more control.

What Does the Board of Health Actually Decide?

The variance is decided 100% by the local Board of Health. You apply, write them a letter, and explain why they should grant it. If the system is functioning and safe, boards should help you out. But just because we think they should doesn't always mean they will.

The Department of Environmental Protection (DEP) sets statewide Title V regulations, but it's up to the local Board of Health to interpret and enforce them. That means there's a lot of town-by-town variation. Some boards are very supportive of ADU development, but others not so much. It's good to know how your board feels about ADUs before you apply, it helps you when making your request.

Board of Health files are all public record. You can go do your own research and see how other people's requests have been decided in your town. If there are a lot of approvals in the past, that sort of sets the standard. If the board granted one for similar circumstances before, it's likely yours will be approved as well.

Which Types of Variances Can You Request?

Several variance types apply to ADU connections. Each one is for different site conditions and has different approval rates based on our experience in Massachusetts.

Groundwater separation requirements depend on the soil perc rates. If the perc test was two minutes per inch or faster, you have to have 5 feet separation. Slower draining soils only need four feet of groundwater separation. Details like this are important when deciding whether a variance request is even necessary.

What Makes a Variance Letter Work?

The variance letter has to show three things. A functioning system, environmental safety, and hardship. Your engineer provides the proof of a working system, then your documents showing your pumping proves the history. Your hardship argument needs to explain why a full replacement would make the ADU financially impossible for you.

System Status Documentation

• Installation year and original design specs
• Last inspection date showing that the septic passed inspection
• Pumping history showing regular maintenance with no issues
• Current bedroom capacity and proposed total after the ADU is built

Environmental Safety Evidence

• Groundwater separation measurement
• Distance to wells and water sources
• No history of failure, backup, or other issues

Financial Hardship Statement

This is a statement saying that to do a complete septic system replacement at a cost of $35,000 to $45,000 would make the ADU too costly to even be possible. You're not arguing against any of the regulations, but are just giving an honest statement about whether you can afford the project or not.

Engineering Support

Your engineer evaluates the system and will let you know if it can safely handle the addition of an ADU. The engineer's letter carries a lot of weight because it is based on their professional liability. When an engineer stakes their reputation on something, the board members will listen better.

What Happens at the Board of Health Hearing?

The hearing is your chance to present your case to the decision-makers. You need to be well prepared for this if you want the best chance of approval.

Actions That Increase Approval Likelihood

• Bring your engineer to answer any technical questions they might have
• Organize records, photos, and documents so you can refer to them easily.
• Always start with environmental safety as your main argument
• Explain your financial hardship respectfully but don't be demanding
• Refer to other approvals that the board has approved in the past
• Offer to accept any conditions like extra inspections or monitoring

Actions That Decrease Approval Likelihood

• Do not argue with board members during the hearing
• It's also never good to compare your situation to a neighbor's approval
• Never threaten legal action during the process
• Don't act like you understand the regulations better than the board
• Keep emotions out of it and just remain calm and helpful

How Does Your Town's Attitude Affect Approval?

Board of Health attitudes can differ a lot from town to town. Understanding your town's feelings on the subject of ADUs can help with how you decide to present your variance request.

What Is the Variance Timeline?

The timeline for getting a variance is somewhere between six to eight weeks from prep to a final decision. For each week there are certain tasks you must complete before you can move forward.

1. Week 1, Preparation: You should gather pumping records, the inspection reports, and site photos.
2. Week 2, Engineering: You need to schedule a site review and receive a letter from your engineer.
3. Week 3, Application: This week you should file a variance request with the local Board of Health which has all attachments.
4. Weeks 4 and 5, Review: The health agent needs to review the application and might ask you for more information.
5. Week 6, Hearing: During this time period you will present your case at a Board of Health meeting.
6. Weeks 7 and 8, Decision: You should get written approval or denial, but be aware that the approval may include conditions.

What If Your Variance Gets Denied?

A Title V pass that you get at the time of sale is no guarantee that your project will meet all the regulations for the ADU expansion. Systems with raised parts and not very much groundwater separation will often get denied because they were approved under a different set of rules.

If your variance is denied, there's still several other ways we can do things.

• We can appeal to DEP if there were clear errors that happened during the review
• We can also redesign the ADU and make it an inside conversion without technically adding any new bedrooms.
• We can build your ADU project in phases, such as upgrading the septic system now and building the actual ADU at a later time.
• We can look into the different choices of treatment systems that require smaller leaching fields.
• We can reapply after new people are elected to the board.

Is a Variance Always the Right Approach?

Variances work the best for functioning systems that already have good recorded maintenance history and the perfect site conditions. If your current system has a history of failure, sits on less than perfect soils, or is too close to sensitive environmental areas, to request a variance could be a waste of both your time and money. If that is the case, you may want to come up with a plan and a budget for a whole new system from the beginning. That way you can plan all the costs for the full project accurately.

Some towns are very strict and usually deny variance requests. If your engineer has recent experience with your specific Board of Health and advises against requesting a variance, it's best to listen to him. The goal is to make sure we can build an ADU, not win an argument.

Ready to Evaluate Your Septic Variance Options?

Always try for the variance because the worst the board can say is no. And when it works, you could possibly save up to $20,000 to $45,000 and keep your ADU project going. So start by gathering your pumping records and inspection history, then contact an engineer who is experienced with your town's Board of Health.

For more information about septic systems and ADUs, read our complete septic series starting with How Do You Handle Septic Systems for ADUs at buildx.com.