(And How I Fix It for Good)

You flip the switch.
The garbage disposal hums… and suddenly, dirty water backs up into your sink.

It’s gross, stressful, and — let me guess — it always happens when you’re cooking or cleaning up.

I’ve unclogged hundreds of disposals around Sacramento, and I can tell you:

It’s fixable. And you’re not alone.

Let me break down the real reasons your garbage disposal backs up into the sink — and what we do to fix (and prevent) it.

What “Backing Up” Really Means

When water — or worse, food sludge — comes up instead of going down, you’ve got a blockage somewhere after the disposal.

The disposal itself may still grind, but the water has nowhere to go — so it comes back up.

Sometimes it backs into:

• The same side of a double sink
• The other side of the sink
• A nearby dishwasher drain

Common Causes I See on the Job

1. Clogged Drain Line

This is the most common issue — especially in older homes.

Over time, food particles, grease, and soap scum form a thick sludge that narrows the drain.

Disposal sends water into the pipe — but it hits that blockage and returns to your sink.

2. Improper Installation or Missing “P-Trap” Drop

If the drain lines aren’t angled correctly, or the trap is installed backwards or flat, water can’t drain by gravity.

Instead, it flows back — or just sits.

I’ve seen DIY jobs where both sink sides are connected in weird ways that guarantee backups.

3. No Air Gap or Dishwasher Backflow

If your dishwasher drains through the disposal and lacks an air gap or high loop, it can push dirty water back into your sink.

Yup — that smell? It might be from the dishwasher line, not just the disposal.

4. Overuse or Wrong Materials

Some people think disposals are invincible.

But if you regularly grind:

• Fibrous veggies (celery, corn husks)
• Pasta or rice (they expand!)
• Grease and oil
• Coffee grounds
• Eggshells in bulk

…it’ll catch up to you.

How I Fix It

When I show up on a call for a backup, here’s what I actually do:

Step 1: Clear the Line

• I disassemble the trap and tailpiece to check for clogs
• If needed, I snake the line further into the wall
• I flush the line hard with hot water + enzyme cleaner

If the water drains freely — we move on to prevention.

Step 2: Inspect the Setup

• Is the trap installed correctly?
• Are both sinks properly vented and pitched?
• Is the disposal mounted tight, no leaks?

I’ll show you if something’s off — and explain why it matters.

Step 3: Educate and Prevent

I always give clear “do and don’t” tips based on your setup.

In some cases, I’ll recommend:

• An enzyme cleaner once a month
• Re-routing lines
• Upgrading the disposal if it’s underpowered or leaking

Quick Home Tips to Prevent Backups

• Run cold water before, during, and after using the disposal
• Avoid putting stringy, starchy, or greasy foods in the unit
• Don’t overload it — feed scraps slowly
• Run the disposal regularly to prevent buildup
• Clean with baking soda + vinegar every couple weeks

What We Do at Golden Valley Plumbing

When you call us, we:

• Clear blockages the right way (no guesswork)
• Check every part of the system
• Fix leaks, traps, and mounting issues
• Recommend smart upgrades if needed
• Treat your kitchen like it’s our own

Sink backing up and you’ve had enough? Call Golden Valley Plumbing — we’ll get it flowing again, fast and clean.

Final Word

A backing-up sink doesn’t always mean a big repair.

But ignoring it?
That’s how you end up with mold, smells, and a broken disposal.

Let’s fix it once — and make sure it doesn’t come back.