Jeremiah:
First off --
1.) What type of building or buildings are we talking about here ???
If they are in multiple separate locations you should have a different master key system for each separate location rather than one for everything...
If it is all in one building you could appeal to the safety safe of your tenants' personalities, and tell them that you are establishing a master key system so that emergency life safety personnel (such as the fire department) can gain access to all the units in an emergency... Fire or medical emergencies... I have not seen many large buildings that haven't had some type of "knox box" near the main doorway or fire alarm box to hold keys for the fire department...
2.) What type of locks do you have installed now ???
Even if they are all compatable and can be keyed into a system together, what condition are they in ??? Are they 5-pin or 6-pin ??? This would be an invest ment in your own personal sanitiy here so you should get all brand new COMMERCIAL grade locks with at least a 6-pin cylinder...
3.) You DO NOT need to buy super security locks... Brian suggested here in the newsgroup that you go out and spend money on Medeco locks... That just multiplies the expense of master-keying your apartments... (It costs WAY more) And it only adds a layer of protection against re-keying, it won't stop one of your tenants from taking that very expensiove lock out of the door and replacing it with the one they just bought at Home Depot... As far as re-keying is concerned AFTER you master key your buildings this should put your concerns to rest:
ALOA Technical Standards Policy Item # 10: When master keying is encountered, then the key presented without its corresponding master key is presumed to be a subordinate key until otherwise determined. An attemot must be made to determine the holder of the master key and seek authorization for cylinder changes or key origination before such service.
Any honest, qualified locksmith will follow that standard and seek out the owner of the property before they change anything about the lock... And finding you is made easier when you invest in a sign that describes who the owner of the porperty is that you put up in some readily viewable place...
4.) I would not use Joe's advice (it is ok advice if you only have one or two units) because in order for that idea to work you would have to keep all those sealed boxes with the keys inside of them with you in order for them to be of any use... Unless you have a VERY secure place to keep them handy at each location...
5.) I agree that you need to change the language of your lease agreements... Check with an attorney to see what language would be allowable under Georgia state law... But in the end, it is YOUR property so you do have the right to require tenants to provide you with a key, or compel them to use your master keyed locks. The law allows landlords and property owners access to units in case of 'emergency' but also to do periodic inspections of the property to ensure that everything is safe and in good working order... (Especially things like smoke detectors and hot water heaters and furnaces and the like, the kinds of things tenants could report you to various governmental authorities and get you in trouble if they are not working properly...)
It is my experience (working in a complex of commerical office buildings) that tenants will often rekey things inside of thier units and simply move out and NOT care if they left the correct keys behind 9 times out of 10... Only if they have some sort of financial incentive do they ever pay attention to handing over all of the keys...
6.) Roger's idea is a good one, but rather than having an extra lock around to install yourself you should simply call your locksmith out to re-key the locks on site before the new lease goes into effect... This is a more beneficial way to do it for these reasons:
a. You now have a locksmith's bill for service that you can keep for your files to PROVE that you re-keyed the locks should a legal dispute ever arise over that fact... b. The locksmith installs and re-keys locks day in and day out, I am not saying that you aren't skilled enough to do this yourself, but you are involving rental property and liability into the equation so leave it to the professsionals who are knowledgeable and insured in the event anything ever went wrong...
I hope that the above comments can help you in some way... I am not a 'professional' locksmith, only a maintenance worker who has some knowledge in that particular area... Good luck with your problem...
Evan the Maintenance Man