Who do I contact for septic permits and inquiries?

Applications for septic systems being installed or replaced can be directed to the Mississippi Valley Conservation Authority office for processing. 

Digital forms can be emailed to mrsso@mvc.on.ca or paper copies can be delivered to the MVCA head office at 10970 Highway 7, Carleton Place on weekdays from 8:30 a.m. to 4:30 p.m. Inquiries can also be made via email to mrsso@mvc.on.ca or by calling 613-253-0006


Forms, fees, frequently asked questions, and other sewage system resources are available for landowners and contractors at www.rvca.ca/septic-approvals

 Who do I contact for well questions?

Please click the following link for Well Design and Wellhead Protection information from the Ministry of Environment or contact them at 1-800-267-0974.

Do I need a building permit for a wood stove?

Yes, you will need to apply for a building permit to install a wood stove, wood burning appliance or Solid Fuel Burning Appliance.

Please see the link below for the building permit application process:

Procedure for Building Permit Applications


You will be required to fill out a Building Permit application form, Schedule 1: Designer Information Form (please note that Schedule 1: Designer Information Form is to be filled out by the Wood Burning Appliance Installer), and a sketch of the proposed location of the stove.


Please keep in mind that you will need a WETT Certificate from the installer prior to booking your inspection once the wood stove is installed.

Do I need a building permit for a Temporary Winter Shelter or Portable Garage?

Under Mississippi Mills Zoning By-law 11-83, temporary winter shelters or portable garages are considered ‘accessory structures’ and are required to adhere to the requirements of the Zoning By-law. Accessory structures must adhere to the same front yard setbacks as the house (principal dwelling), which means that in most circumstances, any portable garage must be located behind the front wall of the house. In the case of attached garages, the Zoning By-law considers attached garages as part of a house (principal dwelling), which means that in most cases, a portable garage would not be permitted to be located in front of an attached garage.


Under Div. C Section of the Ontario Building Code - a temporary car shelter is considered a tent and will require a Building Permit if it is described as one or all of the items listed below:


- larger than 60 square meters (645 square feet) in ground area

- attached to a building

- closer than 3 meters (9.8 feet) to other structures


If you would like to apply for a building permit please visit our Building and Renovation webpage on our municipal website where you will find a building permit application form and other useful information.


If you have further questions please don’t hesitate to contact the Building and Planning Department at 613-256-2064 ext. 508.

I am building a new house or adding an addition to my building in the rural area of Mississippi Mills, do I need to contact the Lanark Leeds Grenville District Health Unit (LLGDHU)? 

Yes, all additions and new home construction that increases living area and/or water usage needs approval from the LLGHDU prior to the Building Department issuing any permit. 

What is applicable law? 

Applicable law  are outside agencies and laws that are required to be consulted and approved prior to permit issuance.  Such agencies/acts include but are not limited to:
- Lanark Leeds and Grenville District Health Unit
- Mississippi Valley Conservation Authority
- Ministry of Natural Resources
- Ministry of Environment

- Planning Act

Any permit that falls under the jurisdiction of one of these Applicable Authorities requires their approval in full prior to any permit being issued by the Mississippi Mills Building Department and other fees may be levied by these agencies for their services. 

I bought a pre-manufactured wood, plastic or metal shed over 160 sq ft and I plan on putting it up, do I need a permit for this? 

Yes, even pre-manufactured sheds of metal, wood or plastic construction are required to meet the structural and design requirements of the most current Ontario Building Code.  Be aware that pre-manufactured sheds normally require a Professional Engineer (from Ontario) to sign off on structural stability of the shed.  Most pre-manufactured shed suppliers will have these documents readily available for you, but some do not and those costs may come out of your pocket. 

Are all items sold at Home Depot, Home Hardware, Rona and other building supply stores legal for use in Ontario? 

The answer to this question is no, not all products you see on the shelves at these stores meet Ontario Building Code requirements for structural integrity and meeting specific design standards.  If you plan on using products like deck railings, deck guards, 4x4 post holders for decks, electrical  and plumbing products you are encouraged to ensure that they meet the standards and ask the supplier to provide this information for you.  If you are still unsure you can contact the building department at (613) 256 2064 x260 and we can assist you with any questions. 

I cut all my own wood and want to use it to build my new deck, shed, house or any other structure.  Is this ok? 

Rough cut lumber is permitted to be used in such projects but it must be graded by a qualified lumber grader from Ontario.  Without the stamp/documents showing that the lumber being used has been graded it will not be permitted. 

I was told that I don't need a deck permit if it's not attached to the house and is less than 10m2 in size, is this correct?    

This is both correct and incorrect.  If the deck is appurtenant to a building (meaning it serves the building directly) via a doorway of any kind then a permit is required for the deck even if it is less than 10m2.  However if you construct a stand-alone deck in your yard that is less than 10m2 a permit is not required. 

I am changing my toilet for a new low flush toilet and my tap fixture, do I need a permit for this work? 

No, a permit is not required when changing a fixture for a new one.  If there is a alteration of drainage or vent pipe and movement of fixtures to other locations in the bathroom, kitchen or any other area then a permit would be required to review the alteration meets code. 

When I build an addition onto my existing house can just I extend my duct work to the new addition without a design? 

The addition of new ductwork to an existing Heating System can cause an imbalance in the system and create issues with airflow, efficiency and temperatures in other rooms in your house.  When you do an addition you will require a duct design from a registered HVAC designer to ensure the furnace can handle the addition and to ensure you have a balanced properly working furnace.  Please visit our Building Permit Information page to review contractors and designers. 

Can my contractor draw plans for me for my renovation in my house? 

No, the Ontario Building Code is very specific that the only persons who can design or submit drawings are the Owner, an Architect or a Registered BCIN Designer as defined by the Ontario Building Code. 

If I build without a permit is there a penalty? 

Yes there is a penalty for building without a permit.  You are subject to a potential ticket for up to $300 and an administration charge on your permit when acquired of anywhere from $500 to $2000.  If you call before your project starts for clarification any of our Inspectors or the Chief Building Official will gladly advise you whether or not you need a permit for your project. 

What constitutes a building?

As Building is defined by the Building Code Act:

"building" means,
(a) a structure occupying an area greater than ten square metres consisting of a wall, roof and floor or any of them or a structural system serving the function thereof including all plumbing, works, fixtures and service systems appurtenant thereto,

(b) a structure occupying an area of ten square metres or less that contains plumbing, including the plumbing appurtenant thereto,

(c) plumbing not located in a structure,

(c.1) a sewage system, or 
(d) structures designated in the building code.

Can I build any size slab on grade detached garage with a basic slab design?

No you cannot, garage over 55m2 in area or any garage that supports loads from the superstructure (a second story) requires a slab designed by a Professional Engineer as per the 2012 Ontario Building Code.

If I build a new addition on my house can I just put the same amount of insulation in the ceiling and walls as there is in the existing house?

No, the insulation values for the new addition are determined in SB-12 of the Ontario Building Code.  When doing the design you will have to be aware of this and complete and Energy Efficiency Design Summary and use the appropriate table and detail the proper amount as required.  If you are not comfortable with this any BCIN Designer that would prepare the building plans for your project can prepare this document for you.

If I bring my permit application in and I am missing items that are required what will happen?  How long once the application is complete will it take to issue permit?

At the time you bring in the application we will review it with you and advise what items are required and you will be required to take all documents and return when you have all required paperwork to make a complete application.  Once it is complete depending on the project it can be either 10, 15, 25, or 30 working days to be reviewed.  Most of our residential applications allow us 10 working days for review.

Are there any permits that don't require drawings?

There are a rare few situations where a drawing isn't required.  Those potential situations include a demolition permit for the removal of a basic structure, a change of use permit that requires no compensating construction, or an outdoor wood burning stove that only requires a site-plan showing the location of the unit.  If no drawing is required the Chief Building Official or Inspector will advise you accordingly.

I plan on changing the use of an entire existing building or just part of the building, do I need a permit?

Potentially, the Ontario Building Code details when a "Change of Use" permit is required and when compensating construction is required.  If you are unsure the Chief Building Official or Inspector can advise you if you require a change of use permit.  These changes often require a BCIN Designer to be involved for code analysis for permit drawings as the plans analysis for these projects is above and beyond the ability of most owners or needs a Designer to be involved.  The Chief Building Official or Inspector can advises you further on these details.

I have all my plans and applications in place and I want to bring it in for an inspector to review and start the permit process do I need an appointment?

Appointments are encouraged because it ensures that an Inspector or the Chief Building Official will be present at the office to review your plans with you.  If no appointment is made you take the chance of not being able to be seen by an inspector onsite when you arrive (due to other appointments or other work having to be completed) so that being said we always suggest you call (613) 256 2064 x260 and seek to set an appointment, especially during the summer months.

If I didn't call an inspector for a prescribed inspection and just took pictures and continued with construction is this adequate?

Pictures can be accepted by the Chief Building Official or Inspector if permission is attained prior by the building official to do so.  Pictures in place of inspections are not encouraged and do not have to be accepted by the Building Department.

Small projects like a deck, landing or shed don't require a site-plan do they?

All projects that involve extension of the building envelope of an existing building, addition of a deck or new structure require a detailed site-plan.  The site-plan allows the inspector to review the location of the changes on the site and check zoning setbacks, proximity to water courses, power line locations, proximity to other buildings on the lot and total coverage of the lot.  All these things are paramount to whether or not your building application will be approved.

Do I need a permit to finish my basement?

Yes, all basement finishing is subject to a permit from our department.  You will need to provide a floor plan with accurate room dimensions showing items such as all rooms, hallways, window locations and sizes, washroom layout and location of existing and new fresh air supply's and cold air returns.  This allows the Building Department to review all code related items and easily and quickly get a permit out to you as soon as possible.

I was told you can put a basement apartment in any dwelling unit in Mississippi Mills, is this correct?

No, Not all dwellings in Mississippi Mills are allowed to have apartments in the basement. The current Zoning By-Law only allows basement apartments in single family dwellings in specific Residential Zones.  The Building Department STRONGLY suggests that if you want to make a basement apartment in your home that you check with the Planning Department at (613) 256 2064 x260 prior to applying for a Building Permit. Building permits are always required to convert any existing residential space into a new apartment dwelling unit. Items that need to be considered include sound transmission between units, fire separations and exiting.

I am replacing deck boards on my front or rear deck, just the walking surface boards do I need a permit?

Replacement of deck boards on a deck or steps serving a deck are considered maintenance work and does not need a permit.  However it is important to remember that normal 5/4 Deck Boards are rated for a maximum 16" o/c spacing.  Larger dimension (2x6's or 2x8's) lumber will span further with proper support for spans up to 24" which is the maximum span of any deck floor joist.