Thanksgiving and the winter holidays are the busiest weeks of the year for most home kitchens. More cooking means more grease, more food scraps and more dishes, and in older Philadelphia homes that extra load often shows up as a slow kitchen sink, a gurgling dishwasher or, in worse cases, a backup in the basement.
Most holiday drain problems are preventable. This guide explains why grease is the main culprit, how to use a garbage disposal without clogging the line, what the Philadelphia Water Department advises, and how to tell a simple sink clog from a problem in the sewer lateral.
Why Grease Is the Main Problem
Hot grease pours easily, so it seems harmless. The problem starts when it cools. The Philadelphia Water Department explains that once fats and oils cool, they can harden, build up and clog pipes, and that this often happens in the lateral pipe that connects a home to the City sewer system.
That last point matters for homeowners. In Philadelphia, the lateral from the house to the City sewer is the property owner’s responsibility. PWD also notes that a grease clog can lead to needing a plumber and could even result in a Notice of Defect if the clog causes problems on your block.
Grease does not stay where you pour it. It coats the inside of the kitchen drain, the branch line in the wall or basement, and the building drain, collecting food particles and soap residue as it goes. Older cast iron drains in Philadelphia rowhomes have rough interior surfaces that give grease more to cling to.
What PWD Recommends
PWD’s guidance for residents is simple:
•Never pour oil, fat or grease down the drain.
•Cool fat or grease, put it in a can or other disposable container, and put it in the trash.
•This applies to all cooking fat, including oil from deep-frying and bacon grease.
An older PWD grease disposal guide adds that soaps, detergents and caustic chemicals do little to combat grease: grease softens temporarily but solidifies again further down the line. The same guide notes that these chemicals can damage drains.
Holiday Kitchen Habits That Protect Your Drains
Before washing
•Wipe greasy pans with a paper towel before washing, and put the towel in the trash.
•Scrape plates into the trash or compost, not the sink.
•Pour roasting pan drippings into a container once they cool slightly. Turkey fat is one of the biggest holiday contributors.
At the sink
•Use a sink strainer to catch food particles.
•Do not rely on hot water to flush grease. Hot water only moves grease further into the pipe before it cools.
•Spread out heavy loads. Running the dishwasher, sink and disposal at the same time sends a large volume through the drain at once.
Fryer oil
If you deep-fry a turkey, plan for the oil before you start. Let it cool completely, then put it in sealed containers for disposal. Never pour it into a sink, toilet, yard or storm drain.
Using a Garbage Disposal Without Clogging the Line
A garbage disposal grinds food into small particles, but it does not make grease or certain foods safe for the drain. Problem items include:
•Grease, oil and fat, for the reasons above.
•Fibrous scraps like celery, onion skins, corn husks and artichoke leaves, which can wrap around the grinder or form mats in the pipe.
•Starchy foods like potato peels, pasta and rice, which can form a paste.
•Coffee grounds and eggshells, which can settle in the trap and the drain line.
•Bones and fruit pits, which most residential disposals are not designed to grind.
Tips for using a disposal:
•Run cold water before, during and after grinding.
•Feed food in small amounts.
•Let the disposal run until grinding stops, then run water a little longer.
•If it hums but does not turn, turn it off. Do not put your hand in the unit.
Why the Dishwasher Is Often Part of the Problem
In most kitchens, the dishwasher drains through the sink’s drain line or the disposal. If the line beyond the sink is partially clogged, the dishwasher may leave standing water, or water may back up into the sink when the dishwasher drains. A dishwasher that suddenly drains poorly during a busy week is often a sign of a kitchen line clog, not a broken dishwasher.
Sink Clog or Sewer Lateral Problem?
How you respond depends on where the blockage is.
Signs the clog is local to the kitchen
•Only the kitchen sink drains slowly.
•Bathroom fixtures drain normally.
•The problem started after a heavy cooking day.
Signs of a problem further down the line
•Several fixtures drain slowly at the same time.
•Toilets gurgle when the kitchen sink or washing machine drains.
•Water appears at a basement floor drain or the lowest fixture in the house.
•The kitchen sink has clogged repeatedly in recent months.
If water is backing up at the lowest point of the house, stop using water and get the line evaluated. Repeated clogs often point to grease buildup, a sag in the line or a damaged section, and a camera inspection can show which one.
What Not to Do
•Do not pour chemical drain cleaners into a disposal or a standing sink. They can damage pipes and create a hazard for whoever opens the drain next.
•Do not keep running water into a backed-up drain.
•Do not use a plunger on a sink after chemicals have been added.
•Do not assume a cleared clog solves the problem. If grease has been building for years, a quick fix may not last.
Frequently Asked Questions
Can I pour grease down the drain if I run hot water with it?
No. The Philadelphia Water Department advises never putting oil, fat or grease down the drain. Hot water moves grease further into the pipe, where it cools and builds up.
Are garbage disposals bad for Philadelphia plumbing?
A disposal used correctly is generally fine. Problems usually come from grease, fibrous and starchy foods, and overloading. Older drain lines with buildup are less forgiving.
Who is responsible for a clogged sewer lateral in Philadelphia?
The property owner is generally responsible for the lateral that connects the home to the City sewer. PWD notes that a grease clog in this pipe may require a plumber.
Why does my dishwasher back up into the sink?
Usually because the shared drain line beyond the sink is partially blocked. Clearing the kitchen line typically solves both problems.
Prevention Is Easier Than a Holiday Backup
A few simple habits, like collecting grease in a can, scraping plates into the trash and going easy on the disposal, prevent most holiday drain emergencies. When drains slow down despite good habits, it is worth finding out why before the next big meal.
Philadelphia Plumbing Experts – Repairs & Installations LLC clears kitchen drains and evaluates recurring clogs in older Philadelphia homes. Learn about our drain and sewer cleaning services.