Trash and garbage are the Back Bay's perennial problem, unsightly as well as unhealthy.

A year ago, the streets and alleys of the neighborhood were filthy, littered with trash and garbage. The problem has come back. Take a walk along any alley before and after trash pickup days. It's a feast for the senses, and for the rats that plague the neighborhood.

What is going on? Have people suddenly lost their normal sense of propriety and decided to become slobs? Not completely. This is a phenomenon that seems to occur annually as residents return from vacation and rental properties turn over at the end of August.

As most residents know, rental properties in the Back Bay typically turn over on September 1. This is the cause of the three-day, hurricane-like event that turns every street from Beacon Hill through Brighton into a garbage dump. As surely as summer begets autumn, moving begets trash. New tenants, stunned to discover that $1,200 a month is buying them a place so small that they need to walk outside to sneeze, have no place inside to store their trash. Outside it goes.

Longer-term residents are not without fault, either. August's end means we begin to contemplate with panic the onset of winter. We reassess our needs, dumping our summer-related possessions and cleaning up our homes. The piles of trash mount. Outside they go.

Combined with the Labor Day holiday, the everyday activities of scavengers, and the occasional crushed bag from trucks and cars traversing the alleys, Back Bay turned into one large refuse area. The City has implemented a tough new policy cracking down and tenants and landlords who leave trash outside. New staff has been hired and the Inspectional Services division, the City agency charged with enforcing trash rules (is it — or is it Code Enforcement??), has been out in force.

But the City cannot do it alone. Residents need to assist. A few thoughts:

• Find out when trash is picked up for your building. Usually it's two times a week (for example, Monday and Thursday) in the morning. Put your trash out only at those times.
• Don't put out your trash at night. Put it out the morning of pickup. Trash bags left overnight become magnets for rats and scavengers.
• If for some reason your trash is not picked up, do not leave it out. Bring it back inside and save it for the next trash pickup.
• Put recyclables out separately, on the first trash day of each week. If you have returnable bottles and cans, put them in the recycling bin so scavengers can find them. Much of the area's trash problems occurs when scavengers slice open plastic trash bags looking for returnables.
• Finally, look around the outside of your building. If there is paper and other refuse, please pick it up. It's annoying, particularly when it's not of your making, but no one else is going to do it.