B100a / Change in Use Application & Building Conversion Instructions

This form is used to follow the State of Connecticut Public Health Code, Section 19-13-B100a, which governs building conversions and/or changes in use to existing structures, building additions, garages/accessory structures, swimming pools and sewage disposal area preservation.

This form provides the local health department with important information to assure you:
Do not build any structures on top of an existing septic system
Conform to the required separating distances and maintain your property according to the Connecticut Public Health Code

In addition to filling out this form, you also have to submit the following:
A written description of the proposed addition, accessory structure or pool.
Existing soil test data, if available.
Proof of ownership, if recent transfer of property (purchase not reflected on town property card), have a copy of your deed. This information can be obtained from your Town’s website or Clerk’s office.
A plot plan drawn to scale (Example: 1inch = 20 feet) which shows the location of the house, well, sewer line, and closest property lines. Be sure to indicate distances between each item.
A building plan, if proposing an addition to an existing structure be sure to include a sketch of the existing floor plan and a sketch of the proposed floor plan change.

Exemptions
You ARE NOT required to file a B100a Application for the following:
Accessory buildings or sheds less than 200 square feet which will sit directly on pressure treated plywood or concrete blocks and do not require the pouring of a concrete slab, frost protected footings, sonar tubes or any other foundation that would disturb the soil.
Anchoring kits that prevent uplift due to winds which are used for temporary structures like removable carports. Anchors should not penetrate the septic system. (Please note, anchoring kits that require the pouring of a concrete slab or permanent footings do require a B100a application.)

In the event of application withdrawal by the applicant, NDDH reserves the right to retain a non-refundable processing fee.
In order to avoid unnecessary delays, please be sure to complete the form in its entirety and submit all required information and fees.

Return by mail, drop off at the office, or use the NDDH drop box. For additional assistance, please contact us at email@nddh.org

State of Connecticut Public Health Code, Section 19-13-B100a information:
Building conversion, change in use. If public sewers are not available, no building or part thereof shall be altered so as to enable its continuous occupancy by performing any building conversion, nor
shall there be a change in use unless the local director of health has determined that after the conversion or change in use, a code-complying area exists on the lot for installation of a subsurface sewage disposal system…

Building additions. If public sewers are not available, no addition to any building shall be permitted unless the local director of health has determined that after the building addition a code-
complying area exists on the lot for the installation of a subsurface sewage disposal system…

Attached or detached garages, accessory structures, below or above ground pools. If public sewers are not available, no attached garage, detached garage, accessory structure, below or above
ground pool shall be permitted unless the local director of health has determined that after construction of the attached garage, detached garage, accessory structure, below or above ground pool, a code complying area exists on the lot for installation of a subsurface sewage disposal system…

Sewage disposal area preservation. If public sewers are not available, no lot line shall be relocated or any other activity performed that affects soil characteristics or hydraulic conditions so as to reduce
the potential repair area, unless the local director of health has determined that after the lot line relocation or disturbance of soils on the lot a code-complying area exists for the installation of a subsurface sewage disposal system…

File #: 	

B100a / Change in Use Application

Street #: 	 Street Name: 			 Town: 		 Year Built: 	 Assessor’s Map: 	 Block: 	 Lot: 	 Dev. Lot: 	 Lot Size: 		 Pole #: 	

Legal Owner: 	
Mailing Address: 	
Town: 	 State: 	 Zip: 	
Email Address: 	Telephone:
Agent for Owner: 			 Agent’s Mailing Address: 			 Town: 	 State: 	Zip: 	
Agent’s Phone Number: 	Email:	
**Contractors that conduct renovation, remodeling, or paint removal activities on residential houses, apartments and child-occupied facilities built before 1978 MUST be EPA Certified to follow lead-safe work practices**

Occupancy Type:
Residential   Single family   Two family   Multifamily 3+   Apartments/condo
Commercial   Office/bank building   Retail store/mercantile   Warehouse/storage   Nursery/greenhouse
  Service station   Hospital/institutional   Parking garage   Theater/recreational   Hotel/motel
  Restaurant   Salon (hair/nails/eyelash)
Municipal	 Public works/utility building   School/educational building
Non-profit	  Church/religious bldg.   Hospital/institutional bldg.   Private club   School/educational bldg.
Agricultural   Nursery/greenhouse   Farm

Proposed Activity* (design flow requirements are subject to change at the discretion of NDDH):
*See NDDH Fee Schedule for applicable fees

Simple: (no change to design flow):
Accessory structure (select from the following)
  Deck/Porch   Shed   Garage   Propane tank    Generator pad   Solar array
  Above ground pool (with/without deck)   Inground pool (with/without concrete pad)
  Other: Please describe	
Lot line change (no free split per PHC Sec. 19-12-B100a(e)Sewage disposal area preservation)
Complex: (increase in design flow):
Residential addition (renovation, basement finishing, house teardown, replacement/repair)
Residential seasonal conversion
Nonresidential change of use, addition, or renovation

Additional documentation required:
Written description of project details:
Please provide a description of the proposed structure or activity including the dimensions of the structure (e.g., “addition with 12’x14’ bedroom, 6’x10’ bathroom and 20’x14’ family room”, “20’ above ground pool with 6’x10’ deck”, “winterizing existing porch” or “converting 200sqft office into doggie daycare”).

Year Built: 	 Pole #: 	
Is the property served by a septic system? Yes 		 No 		 Age of system: 	 Is the property served by an on-site well? Yes 	 No 	
Soil Testing:
Soil test data (deep test pits and percolation test) may be required for the review of this application. If soil test data is NOT available in your property file, you will be notified by the health district. Additional applications and fees will be required for soil testing. Upon receipt of the application and fees an appointment will be scheduled. If you have any questions regarding the soil testing, please contact the office directly.
Proof of ownership:
If the property was recently purchased and your information is not updated on the town property card a copy of the deed will be required.
Building plan:
Attach a sketch/floor plan of the existing and proposed structure additions or renovations. If applicable, include the following information:
Number of bedrooms in existing house:		 Number of bedrooms after addition:	
The addition will have the following:
	Heat 	Plumbing 	Exterior sewer pipe 	Interior sewer pipe 	Full foundation
	Frost wall 	Slab 		Piers 	Other:		 Footing drains: Yes	 (show on plan) No	
Cuts in grade <50’ downhill of septic system: Yes	 No	
Plot plan:
Attach a scaled drawing with distances that shows property lines and dimensions, the location and size of existing and proposed structures, and site features such as driveways, well, sewer lines, septic system, drains and watercourses.
Distance of proposed structure/addition from: Septic tank:	ft Leaching area:	 ft Well:	ft Closest property line:	
********************************************************************************************* PROPERTY OWNER: By signing below, you certify that the information provided is a true and accurate description of the addition, accessory structure, or pool. No services will be rendered until payment is received. Return by mail, drop off at the office, or use the NDDH drop box. In the event of application withdrawal by the applicant, NDDH reserves the right to retain a non-refundable processing fee.
(If working on behalf of owner, please attach a signed Letter of Consent)

Signature of Legal Property Owner	Date

NDDH Use Only

File/ID # 	

Date: 	 Fee: 	 Check # 	  CC  E-Check	Cash	Receipt #	

Rev. 03/17/25