how to replace sink drain

Is your kitchen sink drain emitting foul odors, constantly clogged, or showing signs of rust and corrosion? A malfunctioning sink drain can be more than just an annoyance; it can lead to water damage, unsanitary conditions, and even costly plumbing repairs down the line. Replacing a sink drain is a surprisingly manageable DIY project that can save you money on plumber fees and restore the functionality of your sink. With the right tools and a bit of patience, you can tackle this task and enjoy a smoothly draining sink in no time.

A properly functioning sink drain is essential for maintaining a clean and hygienic kitchen environment. Leaks can damage cabinets and flooring, while persistent clogs can disrupt your daily routine. Learning to replace a sink drain empowers you to address these issues promptly and efficiently. By taking control of this common plumbing problem, you’ll not only save money but also gain valuable skills for home maintenance.

What tools and materials do I need, and how do I actually replace the drain?

How do I remove the old sink drain?

Removing an old sink drain typically involves loosening the connections holding it in place. Start by disconnecting the drainpipe (P-trap) from the tailpiece of the drain. Then, depending on the type of drain, you’ll either unscrew a large nut holding the drain body to the sink or loosen screws that clamp the drain flange against the sink basin. With the connections undone, you should be able to push or lift the old drain out of the sink.

The first crucial step is to clear the area under the sink and place a bucket to catch any remaining water or debris. Before you start wrenching, try to assess the condition of the drain assembly. Older drains can be heavily corroded, making disassembly challenging. Penetrating oil can be your best friend here. Spray it liberally on any threaded connections (especially the large nut under the sink) and let it sit for at least 15-20 minutes before attempting to loosen anything. This will significantly reduce the risk of damaging the pipes or stripping the nuts. If the drain is held in place by a large nut, use a wrench (a plumber’s wrench or pipe wrench is often necessary for a good grip) to turn the nut counterclockwise. For drains secured with screws, carefully loosen them evenly. Avoid stripping the screw heads. Once all connections are free, gently wiggle the drain assembly to break any remaining seal and then push it upwards from underneath the sink to dislodge it from the basin. You may need to use a putty knife to carefully cut through any old plumber’s putty or sealant around the drain flange on top of the sink.

What size drain do I need?

For standard bathroom and kitchen sinks in the US, you’ll almost always need a 1 1/2 inch drain assembly. This is the standard size for the drain opening in most sinks and the corresponding plumbing connections.

While 1 1/2 inches is overwhelmingly the standard, it’s always best to double-check before purchasing a new drain assembly. Measure the diameter of the existing drain opening in your sink. This will ensure you get the correct size and avoid compatibility issues. Also, ensure your P-trap and drain pipes are also the same diameter, as mismatched sizes will require adapters and potentially reduce drainage efficiency. Occasionally, you might encounter a slightly larger or smaller drain opening, particularly in older homes or with specialty sinks. If you find that your sink drain opening is not the standard 1 1/2 inches, you’ll need to find a drain assembly that matches the specific diameter. Plumbing supply stores or online retailers should offer a variety of sizes, though non-standard sizes may require special ordering. Take careful measurements and photographs to help the sales representative find you the appropriate part.

How do I properly seal the new drain to prevent leaks?

Properly sealing the new drain involves using plumber’s putty and tightening the connections appropriately. Apply a generous, uniform ring of plumber’s putty around the underside of the drain flange where it will meet the sink basin. Hand-tighten the drain assembly from underneath, then use a wrench to give it an additional snug turn or two, being careful not to overtighten. Finally, ensure all threaded connections are also tightened firmly.

Sealing the sink drain relies on creating watertight barriers at key points. The plumber’s putty forms a compressible seal between the drain flange and the sink basin, filling any small imperfections in the surfaces. When tightening the drain assembly, the putty compresses and expands, effectively blocking water passage. A common mistake is using too little putty or applying it unevenly. Remember to remove any excess putty that squeezes out during tightening for a clean look. In addition to the putty, the threaded connections also require attention. The slip nuts connecting the drain pipes utilize beveled washers to create watertight seals. Make sure these washers are correctly positioned with the beveled edge facing the direction of the seal and that all connections are sufficiently tightened but not stripped. After installation, run water into the sink and check for leaks at the drain flange and all pipe connections. If leaks are found, tighten connections slightly. If the flange is leaking, you may need to remove the drain, apply fresh plumber’s putty, and re-install.

What’s the best type of putty to use for sink drain installation?

Plumber’s putty is the best type of putty to use for sink drain installation. It’s a pliable, waterproof compound specifically designed to create a watertight seal between the drain flange and the sink basin. It’s easy to mold, remains flexible over time, and resists shrinking or cracking, ensuring a long-lasting and reliable seal.

While other types of sealant might seem tempting, plumber’s putty is the tried-and-true choice for several reasons. Silicone caulk, for instance, although waterproof, can be difficult to work with in this application and can make future drain removal problematic. Plumber’s putty, on the other hand, remains pliable, allowing for easier disassembly should repairs or replacements be necessary down the line. Furthermore, the specific formulation of plumber’s putty is designed to withstand the constant exposure to water and chemicals that sink drains endure.

To ensure the best results, use a generous amount of plumber’s putty when installing the drain. Roll it into a rope about 1/2 inch thick and press it firmly around the underside of the drain flange before inserting it into the sink drain opening. As you tighten the drain assembly from underneath the sink, the excess putty will squeeze out. Simply remove the excess putty with a putty knife or your finger, leaving a clean and watertight seal.

How to Replace a Sink Drain

Replacing a sink drain is a fairly straightforward DIY project that can save you money on plumber fees. Here’s a step-by-step guide:

1. Gather Your Materials: You’ll need a new sink drain assembly, plumber’s putty, a basin wrench (or adjustable pliers), a screwdriver, a bucket, rags or towels, and possibly penetrating oil.

2. Prepare the Area: Clear out the space under the sink. Place a bucket underneath the drain to catch any water or debris.

3. Loosen the Old Drain: Use the basin wrench (or adjustable pliers) to loosen the slip nuts connecting the drainpipe to the P-trap. Disconnect the P-trap.

4. Remove the Old Drain: Use the basin wrench to loosen the large nut holding the drain assembly to the sink. You may need to apply penetrating oil if the nut is stuck. Once the nut is loose, you should be able to wiggle the drain assembly free from the sink. You might need a screwdriver to help pry it loose if the old putty is stubborn.

5. Clean the Sink Opening: Scrape away all the old plumber’s putty from around the sink drain opening. Make sure the surface is clean and dry.

6. Install the New Drain:

   • Roll a rope of plumber’s putty about 1/2 inch thick.
   • Apply the putty evenly around the underside of the drain flange.
   • Insert the new drain assembly into the sink opening.

7. Secure the Drain: From underneath the sink, attach the rubber and cardboard washers (if included with your new drain) and then tighten the large nut onto the drain assembly. Tighten the nut securely, but don’t overtighten.

8. Reconnect the P-trap: Reconnect the P-trap to the new drainpipe, tightening the slip nuts securely.

9. Test for Leaks: Run water into the sink and check for leaks around the drain flange and the P-trap connections. If you see any leaks, tighten the connections further. If that doesn’t work, you may need to disassemble the drain, apply more plumber’s putty, and reassemble.

10. Clean Up: Remove any excess plumber’s putty and clean up the area under the sink.

What should I do if the drain pipe is corroded?

If your sink drain pipe is corroded, the best course of action is to replace it entirely. Corrosion weakens the pipe, making it prone to leaks and eventual failure. Attempting a repair on a heavily corroded pipe is usually a temporary fix and not worth the effort in the long run.

Replacing the drain pipe is a relatively straightforward DIY project for most homeowners, although you can always hire a plumber if you’re uncomfortable. The process generally involves disconnecting the old drain assembly (including the P-trap), cleaning the sink drain opening, and installing a new drain assembly, ensuring all connections are watertight. Before starting, identify the type of piping you have (PVC, copper, or galvanized steel) and purchase a replacement drain kit made of compatible materials. Mismatched materials can lead to further corrosion and connection problems. When purchasing a replacement, consider upgrading to PVC or ABS plastic if your existing drain is galvanized steel. Plastic drain pipes are resistant to corrosion and generally easier to work with. Make sure to properly measure the diameter and length of the existing pipes to ensure a proper fit. Always use plumber’s tape (Teflon tape) or pipe joint compound on threaded connections to create a watertight seal. With the right tools and preparation, replacing a corroded sink drain pipe is a manageable task that will prevent future plumbing problems.

And that’s all there is to it! You’ve successfully replaced your sink drain. Pat yourself on the back – you’ve saved some money and learned a new skill. We hope these instructions were clear and easy to follow. Thanks for reading, and we hope you’ll come back soon for more DIY tips and tricks!