How to find out if apt has mouse problem?

let's try to narrow it down. Is the apartment in New York City?

If so, wake up, they are your neighbors.

If you want concrete information, hire an expert to inspect prior to your purchase? Ask the building staff? Ask the owner? Ask the broker? Have your lawyer send a letter?

GMS,
All the things MrSuttonPlace said are fine things to do. However, I wouldn't put tons of faith in the owner, broker, or anyone that has a financial interest in making a sale. The building staff might have an idea. But also, depending on the size of the building, there may be mice SOMEwhere, but 1 unit in a large building may never see them.

One of the things to do in your walkthrough (or before) is to look for evidence yourself. Check for droppings, chewed wood or wires, holes, etc., etc. Especially look under the sinks, in closets, in cabinets, etc. Look for anything that you can think of that might leave a trace. If you find something, that means they're close by.

Additionally, there "technically" should be written documentation of mice in the minutes -- provided there was a legitimate problem that was filed with the board. If the board keeps good minutes (although many don't), there should be evidence of a significant and/or prolonged problem, and it's exact whereabouts. This is something your lawyer should review and expose, should it exist.

Also, if you REALLY want to dig, you can go to the DoB website and see if there were any infestations reported. I believe the DoB has this kind of information if the problem gets to a certain point (say, if charges are filed).

So, in summary, I think if you have this 4-pronged approach, and find nothing, you should be in pretty good shape. Keep in mind, in MANY (if not most) of all the old buildings in NYC, there has been SOME kind of vermin at SOME point in the building's life. That doesn't necessarily mean YOU will have a problem (or even see them). Generally, cleanliness and a good defense (sprinkling borax around in corners and in cabinets, putting out traps) is the best deterrent. But emphasis on the cleanliness.

:)

Mice are a concern, and as UE says, there should be mention in the board minutes if a mouse infestation has been reported. Roaches? They're in every building in NYC. Yes, some are worse than others and some are very good at keeping bugs at bay (we've been lucky, knock wood, and have not yet seen a single roach in our apartment), but there's really no getting away from roaches if you want to live in the Big Apple.

Now, keep in mind that higher floors tend to be less roachy than lower and ground floors. Same generally goes for mice.

Here is a useful site: http://www.nyc.gov/html/hpd/html/home/home.shtml
In the right hand column, under 'complaints, violations etc' - type in the address and all will come up.
I am currently looking - and before I go see a place I check the address here.

In the contract, ask for a clause that asks the current owner to disclose whether there have been any mice/cockroaches. SOmething similar to the bedbug clause that is being placed in contracts today. Buildings/supers often have records of whether certain units have requested any extermination services.