Don’t let a fatberg ruin your holidays!

The River Authority
Nov 22, 2022

Estimated Read Time: 3.5 Minutes

What is a fatberg?

A fatberg is a waste mass in a sewer system made up of non-biodegradable solids like fats, oils, grease (FOG), and wipes. They form when people wash or flush these items down pipes (including sinks, bathtubs, toilets, and showers), and they combine to create a lump that clogs up pipes. Just as cholesterol accumulates in human arteries, these fatbergs can grow so large that they reduce flow capacity and cause inconvenient and expensive back-ups in both a home or a business’s plumbing and sanitary sewer systems.

fats, oils, and greases stuck in pipe

A dreaded fatberg looms in the pipes beneath the streets of San Antonio, ready to ruin holiday cheer.

Why are fatbergs and FOG dangerous?

The buildup of FOGs and wipes, AKA fatbergs, in sewer pipes not only restricts the flow of wastewater from homes and businesses but can also trigger spills known as sanitary sewer overflows (SSOs). YUCK! SSOs can lead to the contamination of your local creek and the San Antonio River and increased costs to you and your neighbors, business owners, and wastewater service providers, such as the River Authority. Additionally, fatbergs in the wastewater collection system can travel all the way to the wastewater treatment plant (WWTP). When this happens, they impact the ability of the microorganisms in the treatment process to properly treat the wastewater. The five WWTPs owned and operated by the River Authority have a combined capacity of over 10 million gallons per day, and fatbergs can be a substantial maintenance issue for these plants.

Be aware of what you’re putting down the drains and flushing down the toilet. Not only will you protect the San Antonio River, but you’ll protect your own pocketbook too!

River Authority Utilities Crew Conducting Line Maintenance

River Authority crew cleaning sewer pipeline using water.

What are examples of FOGs?

Thanksgiving dinner

Keeping track of what we put down our pipes during the holiday season— a time when many of us gather in large groups to indulge in FOG-heavy meals— is crucial.

The list below names the TOP FOG-HEAVY FOODS that could contribute to fatbergs:

  • Animal Fats
  • Butter
  • Dairy Products
  • Desserts
  • Dressings
  • Food Scraps
  • Lard
  • Margarine
  • Oils
  • Sauces
  • Shortening
  • Soups


Instead of washing FOGs down the drain, follow these three easy steps for a fatberg-free holiday season:

Don't dump fats, oils, or grease down the drain.

TIP: You can reuse old jars or cans for old cooking oil, dressing, and other liquid disposables.

Read below for another great way to save $ on your utility bill this winter!

Save $ with Winter Averaging

Piggybank with winter hat standing on top of gold coins


Since the River Authority sewer charges are based on your average winter water use, using less water this winter can add up to savings in 2023. Winter averaging takes the amount of water used in a home during three complete billing cycles from mid-November to mid-March to calculate your sewer fee for the whole year beginning the following July 1. Here are a few tactics to save water this winter:

For more information on how the sewer portion of your water bill is calculated, please see River Authority Wastewater Treatment Benefits.

By doing the above, you can help the River Authority Utilities Department (or your local WWTP utility provider) keep ecosystems of the San Antonio River Basin clean and be proactive in protecting wastewater collection pipes while saving money. That’s River Gratitude!

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