Undue burden and fundamental alteration
The law
The most frequently claimed defence and the least frequently evidenced one.
The two limits
An accommodation is not required where it would impose an undue financial and administrative burden on the provider, or where it would fundamentally alter the nature of their operations. These are real limits and they are not a general reasonableness veto.
Undue burden is fact-specific
It is assessed against the provider resources, not against the tenant. A large management company and an individual owner of one duplex are in genuinely different positions, and the same cost can be undue for one and trivial for the other. What it is never assessed on is assertion: a provider claiming undue burden is making a factual claim and should be able to show the figures behind it.
The insurance argument
The most common version is that the insurer excludes a breed. That is an undue burden argument and it requires evidence: whether cover is genuinely unavailable, what an alternative policy would cost, and whether the provider has actually checked. A clause in a policy document is where that argument starts, not where it ends.
Fundamental alteration
Narrower still, and rarely available in ordinary rental housing, because permitting an animal does not change what a landlord does. It has more traction in specialised settings: a sterile clinical environment, a food production facility, a congregate care programme with infection control obligations.
What a provider should do instead
Consider whether a different accommodation would reduce the burden, and record that they did. A provider who explored an alternative and documented why it would not work is in a far stronger position than one who went straight to refusal, whatever the underlying figures say.
Common questions
- Is cleaning cost an undue burden?
- Almost never on its own, and the provider has an ordinary remedy for actual damage at the end of the tenancy in any case.