Answer: The purpose of a deposit is to reimburse the landlord for any outstanding money that is owed or to cover the costs of repairing any damage over and above "fair wear and tear.

If your landlord does withhold your deposit, he will need to supply you with proof of the repair costs he has incurred (e.g. receipts).

If the repair costs amount to less than your deposit, your landlord must refund you the difference. If your landlord fails to supply you with proof then you may lodge a complaint with the Rental housing tribunal. 

To avoid a situation like this, before you move in, it is required by law to inspect the property with your landlord.

“This response has been prepared for information purposes only and does not constitute legal advice, or a legal opinion, the practical application will vary depending on the facts of each case. Please obtain a full legal opinion from a legal professional or tax practitioner if you wish to act on any aspect hereof as the response is not fully comprehensive. “