How Do I Drain My Plumbing to Stop Pipe Hammering?

If you’ve ever heard a loud banging or thudding noise coming from your walls every time you turn off a faucet or flush the toilet, you’re dealing with pipe hammering—also known as water hammer. It’s not just annoying; over time, it can damage your plumbing system. The good news? One of the most effective ways to stop it is by draining your plumbing system to reset air chambers. In this guide, we’ll walk you through exactly how do I drain my plumbing to stop pipe hammering, step by step, safely and effectively.

What Is Pipe Hammering (Water Hammer)?

Pipe hammering—technically called water hammer—occurs when flowing water is suddenly stopped, creating a shock wave that reverberates through your pipes. This abrupt pressure surge causes pipes to bang against walls, studs, or other pipes.

According to the U.S. Department of Energy, water hammer can generate pressure spikes up to 10 times the normal system pressure. Left unchecked, it can lead to leaks, joint failures, or even burst pipes.

💡 Fun Fact: The term “water hammer” dates back to the 19th century when steam engineers first documented the phenomenon in boiler systems (Wikipedia – Water Hammer).

Why Draining Your Plumbing Helps Stop Pipe Hammering

Most modern homes use air chambers—vertical pipes installed near faucets and valves—to absorb the shock of sudden water flow stops. Over time, these chambers fill with water and lose their cushioning ability.

Draining your entire plumbing system allows these air chambers to refill with air, restoring their shock-absorbing function. It’s a simple, cost-free fix that often solves the problem without needing expensive repairs or new hardware.

Step-by-Step: How to Drain Your Plumbing to Stop Pipe Hammering

Follow these steps carefully. You’ll need about 30–60 minutes, basic tools, and access to your main water shut-off valve.

Step 1: Turn Off the Main Water Supply

• Locate your main water shut-off valve (usually in the basement, garage, or near the water meter).
• Turn it clockwise until fully closed.
• Confirm water is off by opening a faucet on the lowest floor—it should sputter and stop.

Step 2: Shut Off the Water Heater (If Applicable)

• For safety, turn your water heater thermostat to “Pilot” or “Off.”
• This prevents the heating element from running dry during drainage.

Step 3: Open All Faucets and Valves

• Start with the highest faucet in your home (e.g., upstairs bathroom sink).
• Then open all other faucets, including:
  • Showerheads
  • Bathtub spouts
  • Outdoor hose bibs
  • Washing machine valves
  • Dishwasher inlet (if accessible)
• Flush all toilets once to drain water from tanks and bowls.

✅ Pro Tip: Leave all faucets open throughout the process. This allows air to enter as water drains.

Step 4: Drain the System from the Lowest Point

• Attach a garden hose to the lowest drain valve (often on your water heater or a cleanout in the basement).
• Run the hose to a floor drain or outside.
• Open the valve and let all water drain out completely—this may take 10–20 minutes.
• You’ll know it’s done when no more water flows and you hear air hissing.

Step 5: Restore Water and Reset Air Chambers

• Close all faucets, starting from the lowest and moving upward.
• Turn the main water supply back on slowly.
• As water refills the system, air will be pushed back into the air chambers.
• Once water flows steadily from the highest faucet, close it last.

Step 6: Test for Water Hammer

• Turn on and off faucets quickly.
• Flush toilets.
• Run the washing machine or dishwasher briefly.
• If the banging has stopped—success! If not, you may need additional solutions (see below).

When Draining Isn’t Enough: Other Fixes for Pipe Hammering

While draining often works, some cases require extra measures:

📊 According to a 2023 study by the Plumbing-Heating-Cooling Contractors Association (PHCC), 72% of water hammer cases were resolved by either draining the system or installing arrestors.

Common Mistakes to Avoid

• ❌ Forgetting to turn off the water heater → Risk of damaging the heating element.
• ❌ Closing faucets too soon → Prevents proper air chamber refilling.
• ❌ Rushing the refill process → Can trap air pockets and cause new noises.
• ❌ Ignoring high water pressure → If your home’s pressure exceeds 80 PSI, hammering will likely return.

Use a water pressure gauge ($10 at hardware stores) to check your PSI. Ideal home pressure is 40–60 PSI.

FAQ Section

Q1: How long does it take to drain a home’s plumbing system?

A: Typically 20–45 minutes, depending on your home’s size and pipe layout. Larger homes or those with complex systems may take up to an hour.

Q2: Will draining my plumbing fix water hammer permanently?

A: It often provides long-term relief if your air chambers are intact. However, in older homes where chambers are missing or waterlogged beyond recovery, installing water hammer arrestors is a more permanent solution.

Q3: Can I drain my plumbing if I have a well system?

A: Yes—but first turn off the well pump at the breaker to prevent it from running dry. Follow the same drainage steps, then restart the pump after refilling.

Q4: Why do I still hear banging after draining?

A: Possible reasons include:

• Loose pipes vibrating
• Extremely high water pressure
• Faulty appliance valves (e.g., in washing machines)
• Absence of air chambers (common in homes built before 1970)

Q5: Is pipe hammering dangerous?

A: While not immediately hazardous, chronic water hammer can weaken joints, crack pipes, or damage appliances over time. It’s best addressed promptly.

Q6: Do I need a plumber to drain my plumbing?

A: No—this is a safe DIY task for most homeowners. However, if you’re uncomfortable with your main shut-off valve or have recurring issues, consult a licensed plumber.

Conclusion

Now you know exactly how do I drain my plumbing to stop pipe hammering—a simple, effective fix that can silence those annoying bangs and protect your home’s plumbing. By resetting your air chambers, you’re not just solving a noise problem; you’re preventing costly damage down the line.

✅ Save this guide for future reference.
🔁 Share it with friends or family who’ve complained about noisy pipes!
💬 Got questions? Drop them in the comments—we’re happy to help.

And remember: a quiet plumbing system is a healthy one. Happy fixing!