Bought a house: Do I have to pay the city for mowing the grass before I bought the house?

Consider yourself lucky.  In Illinois, we have Public Act 94-1049 for condominiums, whereby the purchaser of the property previously obtained  through a foreclosure sale by/through the lender is liable for up to six  months of past due assessments or the balance of the account, whichever  is less. In one instance, I even had to pay for assessments racked up by the delinquent owner for failure to provide proof of liability insurance ($125) and cursing the property management staff at $25 per infraction.  When you try to negotiate these things down with the HOA, it is fruitless as you are negotiating against yourself as a member of the Association.

I don't think it is as simple as Bruce suggests, and likely depends on the state you are in, and how the local codes are written. Big picture Bruce is right, a foreclosure typically wipes out liens that were incurred later on. There are exceptions! For example past due property taxes stay with the property and become the new owners responsibility upon transfer (in a normal transfer, an escrow agent or attorney usually makes sure these are fairly pro-rated between buyer and seller). The reason I mention property taxes is that I've been unable to eliminate some city and county liens because the local laws are written such that unpaid liens rollover to the property tax roll if unpaid. And as I just mentioned you, as the new owner, are responsible for unpaid property taxes. I'm not sure their position is legally justifiable, but unless you can convince them otherwise it's going to be far more expensive to fight it in court, then to just pay it.