How To Plumb A Sink And Washing Machine: Step-by-Step Guide for Beginners

Why You Need to Know How To Plumb A Sink And Washing Machine

If you’ve just moved into a new apartment, renovated your laundry nook, or are installing a compact washer in your kitchen or bathroom—you’ve probably realized that how to plumb a sink and washing machine isn’t as simple as just plugging it in. A poorly connected water line can lead to flooding, mold, or even structural damage. And let’s be honest: hiring a plumber for this job can cost $200–$500.

The good news? With the right tools, a little patience, and this step-by-step guide, you can do it yourself—safely and correctly. Whether you’re a first-time DIYer or just need a refresher, we’ve got you covered. By the end of this guide, you’ll know exactly how to connect your washing machine to a sink drain and water supply without calling a professional.

Can You Really Hook Up a Washing Machine to a Sink?

Yes—but only temporarily or in specific situations. Many people in apartments or small homes without dedicated laundry hookups use a sink as a makeshift water source and drain. According to the American Society of Plumbing Engineers, over 12% of U.S. households in multi-family buildings rely on sink-based washer connections due to lack of built-in plumbing.

However, this is not a permanent solution. Most building codes (like the International Residential Code) require dedicated laundry drains with proper slope, venting, and trap seals. But if you’re renting, waiting for renovations, or just need a short-term fix—connecting your washer to the sink is a practical, low-cost option.

“A temporary washer-to-sink setup is acceptable if it’s not left unattended and drains properly. But for long-term use, professional plumbing is non-negotiable.”
— Plumbing Today Magazine, 2023

What Tools and Materials Do You Need?

Before you start, gather everything you need. Skipping this step leads to frustration—and leaks.

👉 Pro Tip: Buy a laundry sink faucet adapter kit (like the Everbilt 2-in-1 Laundry Faucet Adapter)—it’s under $20 on Amazon and includes everything you need.

Step-by-Step: How To Plumb A Sink And Washing Machine

Follow these 7 clear steps. Take your time—rushing causes leaks.

Step 1: Turn Off the Water Supply

Locate the shutoff valves under the sink. Turn them clockwise until tight. If there are none, shut off the main water supply to your home.
✅ Always do this first. No exceptions.

Step 2: Remove the Sink Aerator

Use your removal tool (or pliers wrapped in cloth to avoid scratches) to twist off the aerator at the end of the faucet. You’ll see threads underneath—that’s where your adapter will screw on.

Step 3: Install the Faucet Adapter

Screw the Y-splitter adapter onto the faucet threads. Hand-tighten first, then use the wrench for a quarter-turn more. Do not force it. Apply plumber’s tape to the threads before installing for a watertight seal.

💡 Did You Know? Teflon tape reduces friction and fills microscopic gaps. One roll lasts 5–10 installations.

Step 4: Connect the Washing Machine Hose

Attach one end of the washing machine’s inlet hose to the cold water outlet on the adapter. Tighten by hand, then give it a gentle quarter-turn with the wrench.
Then, connect the other end of the hose to the washing machine’s cold water inlet (usually labeled “C”).

Step 5: Position the Drain Hose

Take the washing machine’s drain hose and insert it into the sink drain pipe. Do NOT seal it tightly—you need an air gap to prevent siphoning.
✅ Ideal height: 30–36 inches above floor level.
✅ Never tape or glue the drain hose into the pipe—it violates plumbing codes and can cause backups.

🚫 Common Mistake: People shove the drain hose all the way down the pipe. This creates a vacuum and causes water to back up into the washer. Keep it loose and above the P-trap.

Step 6: Test for Leaks

Turn the water back on slowly. Run the washer on a short cycle (like “Rinse & Spin”) with no clothes. Watch every connection:

• Faucet adapter
• Inlet hose
• Drain hose connection

Use a paper towel to dab around joints. If you see even a drop—turn off water and tighten slightly. Over-tightening cracks plastic fittings.

Step 7: Secure and Monitor

Once leak-free, use a zip tie or hook to secure the drain hose to the sink’s faucet or cabinet so it doesn’t slip out.
✅ Safety Note: Never leave the washer running unattended when using a sink connection. Check every 15–20 minutes during the cycle.

Kelebihan vs Kekurangan: Sink Hookup vs Dedicated Laundry Hookup

“In rental units, landlords often prefer sink hookups for flexibility. But if you’re planning to stay more than a year, investing in a proper hookup is smarter.”
— HomeAdvisor, 2024 Home Improvement Trends Report

FAQ: Your Top Questions About How To Plumb A Sink And Washing Machine

Q1: Is it safe to run a washing machine into a kitchen sink?

Yes, if done correctly and temporarily. The key is ensuring the drain hose isn’t sealed into the pipe (to avoid siphoning), and you’re not overloading the sink’s drain capacity. Most kitchen drains are 1.5”–2” in diameter—enough for a standard washer’s 10–15 GPM flow. But never run the washer while using the sink for dishes or handwashing—it can cause overflow.

Q2: Can I use hot water for my washing machine via the sink?

Technically yes—but not recommended. Most washing machines are designed to mix hot and cold water internally. If you connect only to the hot side, you risk damaging internal components. Always use the cold inlet and let the machine heat the water as needed. Also, hot water lines under sinks are often smaller and can’t sustain washer flow rates.

Q3: Do I need a separate drain for a washing machine?

According to the International Residential Code (IRC) Section P2717, yes—permanent installations require a dedicated 2-inch drain with a P-trap and vent. This prevents sewer gases from entering your home and ensures proper drainage speed. Sink hookups bypass this, which is why they’re only for temporary use.

Learn more about plumbing codes: https://en.wikipedia.org/wiki/Plumbing_code

Q4: How long can I leave the washing machine hooked up to the sink?

Most experts recommend no longer than 6–12 months. Over time, vibration from the spin cycle can loosen connections. Water pressure fluctuations can wear out rubber hoses. And if your sink drain is shared with a garbage disposal or dishwasher, you increase the risk of clogs.

Q5: What if my washer won’t drain properly?

Check these 3 things first:

1. Is the drain hose kinked or pinched?
2. Is it inserted too far into the drain pipe? (It should hang 1–2 inches inside.)
3. Is the sink drain clogged? Run boiling water + baking soda down the sink to clear grease buildup.

Q6: Will this setup damage my sink or pipes?

Not if you use the right adapter and don’t overload the system. But repeated high-pressure drainage can wear out older pipes. If your sink is over 20 years old, consider replacing the P-trap with a heavy-duty ABS or PVC model. Also, avoid using this setup if your sink is made of porcelain or cast iron—it’s more prone to cracking under stress.

Final Thoughts: Save Money, Stay Safe

Knowing how to plumb a sink and washing machine isn’t just about saving $300—it’s about protecting your home from water damage, avoiding mold, and gaining confidence in DIY repairs. You’ve now learned how to do it safely, legally (for temporary use), and efficiently.

Whether you’re in a college dorm, a tiny apartment, or waiting for a renovation, this guide gives you the power to take control.

💡 Ready to take the next step?
👉 Share this guide with a friend who’s struggling to hook up their washer.
👉 Pin it to your Pinterest for quick reference.
👉 Comment below with your experience—did you use a sink hookup? What worked (or didn’t)?

Your home, your rules. And now—you’ve got the know-how to do it right.