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Video · Water Heaters

Water Heater Knocking Ends Here: Old Tank Out, Tankless In

Water heater knocking or popping usually means sediment on the tank bottom, with water trapped under it boiling as the burner fires. This old tank knocked its last, and a tankless took its place.

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What you’re seeing in this video

Snow lines the townhouse street as two techs, one pushing and one pulling, wheel an old tank water heater on a hand truck past a SwiftPro-wrapped truck. Cartoon meme clips pop in between shots for laughs.

The replacement is a wall-hung tankless water heater, with white PVC venting going out and copper piping coming in. With no tank, there's no sediment bed on a tank floor for water to boil under, so that particular noise is gone.

Job footageSwiftPro
Topic
Water Heaters
Length
0:12
Posted
August 2, 2026
Shot by
The SwiftPro crew, Northern Virginia

Why it matters in your house

  • Early knocking can sometimes be quieted with a thorough flush. Once it's loud every time the burner fires, the sediment has usually hardened and the tank is losing efficiency.
  • Knocking in the pipes right when a faucet shuts off is a different problem, called water hammer. That's a pressure issue, not the water heater.
  • A noisy tank past 10 years is telling you the end is near. Replacing on your schedule beats a cold shower on a snowy morning.

Why is my water heater making a knocking noise?

Most often it's sediment. Minerals settle on the tank bottom, water gets trapped underneath, and when the burner heats it, it flashes into steam bubbles that pop and knock. A flush can help if it's caught early. If the noise is in the pipes when you shut a faucet, that's water hammer, and an arrestor or a pressure fix solves it.

Want it done at your place? See Water Heaters at SwiftPro or call (703) 997-9757.

More videos from the SwiftPro crew

A tankless water heater swap in a basement: a gloved hand levels new black iron gas piping with a union and valves, a tech in a gray cap mounts and connects a wall-hung Navien unit, and a tech on a We0:46How Long Does It Take to Replace a Water Heater With a Tankless?A tech in a gray hoodie cuts copper pipe with a pipe cutter on a drop cloth.0:36Water Heater Replacement Process, Heard Up CloseTwo techs cut open an old GE electric water heater in front of a SwiftPro van at the shop, peeling back the insulation to show the inside of the tank.0:38How Does a Water Heater Work? Two Techs Cut One Open to Show YouA wall-mounted tankless water heater being installed in a basement: gloved hands connect the piping, a tech on a ladder solders copper with a torch, and new copper and PVC vent piping.0:38A Wall Mounted Tankless Water Heater Going Up in a BasementTyler Griffin (name on screen) stands in the SwiftPro warehouse between two old tank water heaters, one cut open to show the corroded inside, with a '$500 off New Water Heater' banner.0:35Rusty Water Heater, Outside and In: Tyler Griffin Shows BothA tech walks a homeowner through a gas water heater install in an unfinished basement, pointing at the expansion tank area and piping while captions talk about thermal expansion.1:05Power Vent Water Heater Install: Four Details Worth Seeing

See all 234 SwiftPro videos

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SwiftPro Heating, Cooling & Plumbing
4230 Lafayette Center Dr N, Chantilly, VA 20151
44679 Endicott Dr, Suite 211, Ashburn, VA 20147
Virginia Class A contractor license #2705192276

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