04-52 Storm sewer systems

Question: 04-52Code Section: 7Date:OBC 2006 Reference:

Question: There are 2 storm sewer systems on this property, the first being on the property for site drainage (storm retention) and the second system is for the building.
1. is this plumbing?
2. definition of storm?
3. is a permit required?
4. who looks after this?

(O. Reg. 403/97) We will attempt to answer these questions in a manner that encompasses all parts and not necessarily in order.

The definition of storm drainage should be the key to answering all of the above questions.  However, it is also the most misunderstood.  Storm drainage piping as defined includes storm building drain, storm building sewer, rain water leader, catch basin and area drains installed to collect water from the property and the piping that drains water from a swimming pool or from water cooled air conditioning equipment (basically all piping that conveys storm sewage) but does not include a private sewage treatment and disposal facility designed for the treatment or retention of storm sewage prior to discharge to the natural environment.                      
On the surface, this definition seems clear enough but where the confusion arises is when the site plan comes in labelled as storm management.  We must ensure at the plan review stage which of the piping in the storm system is designed as storm management.  In other words, because a catch basin or a manhole has a flow restrictor in it or that an interceptor is installed at property line, it does not automatically deem the whole system as storm management.

If the piping in the storm system is designed to convey storm sewage to a manhole that has a flow restrictor in it, the piping that conveys the storm is plumbing but the manhole is storm management.  If the piping is designed to retain the water then the whole system upstream of the manhole is deemed storm management and therefore not plumbing.

As for wondering if a permit is required you must verify in your building bylaw to see if these scenarios are covered, we think that most municipalities request that permits be applied for regardless if it is deemed plumbing or not since most of us inspect it anyway.  The other problem lies in the enforcement because if it is NOT plumbing then the OBC does not apply and we must et our authority from other legislation and in this case it would be MoE.  If you want to be certain if it is not plumbing, tell them that it is and let the applicant prove that it is not.