Fix a Leaky Kitchen Sink Where Water Comes Through the Top

A leaky kitchen sink can be a frustrating and concerning problem for any homeowner. Water dripping from the top of your sink not only causes damage over time but also leads to wasted water and higher utility bills. Preventing leaks should be a priority, but even the most diligent homeowner may eventually encounter this issue. Fortunately, with some diligent troubleshooting and basic plumbing repair skills, you can diagnose the cause of the leak and stop that dripping kitchen sink in its tracks.

Finding the Exact Source of the Leak

The first critical step is identifying where exactly the water is coming from. There are a few common culprits for kitchen sink leaks from the top:

• Faulty faucet connections - Worn washers, loose nuts, or damaged O-rings around the faucet supply lines or spout can lead to water dripping down from the faucet.
• Cracked sink basin - Over time, cracks or holes can develop in stainless steel, porcelain, composite, or other sink basins, leading to leaks around the upper rim.
• Improper seal - If an undermount sink is not properly sealed to the countertop with waterproof silicone caulk, water can leak through gaps and seams.
• Plumbing issues - Leaks may come from supply lines or shut-off valves below the sink.
• Drain leaks - A deteriorated drain basket gasket can allow water to seep from the drain.

Start by thoroughly cleaning the sink and faucet area with a soft cloth or sponge. Use a non-abrasive cleanser or baking soda and vinegar solution to remove any grime buildup that may be obscuring potential leaks. Run some water into the sink and check below the cabinet for any drips. Look on the backsplash wall for water marks that may indicate a leak.

If the leak appears to be coming from the faucet connections, tighten the nuts around the water supply lines with a wrench. Tighten the mounting nuts around the faucet base as well. This may seal up any loose connections. Examine the faucet closely under the cabinet for any cracks or damage. Spray the faucet and connections with water to isolate the exact spot the leak is coming from.

For kitchen sinks with two basins, test each basin separately by plugging one side and running water into the other basin. Check below while doing this to determine which side the leak could be coming from. If water appears to be leaking through cracks around the drain basket, remove the basket and inspect the sink basin carefully for any cracks radiating from the drain hole.

Fixing a Leaky Faucet

If you've determined the leak is coming from the faucet itself, some faucet repairs should stop the drip. Many leaks stem from worn washers, O-rings, cartridges, and connections. Depending on the faucet type (compression, cartridge, ball, or disc) the repair procedures vary slightly. Here are some steps to try:

1. Replace old rubber washers and O-rings around valve seats. Over time, these washers get compressed and damaged, causing drips.
2. Tighten the faucet spout. A loose spout can shift and drip from the base.
3. Tighten the faucet handle. Loose handles can lead to internal leaks.
4. Replace worn cartridges or stems. Cartridges control water flow and provide internal sealing.
5. Clean aerators, screens, and shower heads. Mineral buildup here can restrict water flow and cause drips.

When making any faucet repairs, make sure to shut off the hot and cold water supply lines under the sink first. Use silicone plumber's grease on new rubber washers and O-rings during reassembly to help create a better seal. Replace plastic supply tubes and metal braided connectors periodically as they degrade over time and can lead to leaks.

If the leak persists after trying the above steps, you may need to replace the entire faucet. A new faucet can provide a long-lasting drip-free solution. Make sure to select a high-quality faucet model designed to prevent leaks. While more costly, installing a brand new faucet can be a wise investment and often isn't too difficult for an experienced DIY-er. Hiring a plumber is also an option if you are uncomfortable making the replacement.

Repairing a Damaged Sink Basin

If the source of the leak appears to be a crack, hole, or gap in the sink basin itself, you'll need to take steps to seal it up properly. The location and severity of the damage will impact your repair options. Here are some tips to stop basin leaks:

• Clean and dry the damaged area thoroughly. Remove any old putty or sealant completely.
• Apply a waterproof epoxy formulated for sink repairs. Work it into cracks and gaps. Allow proper curing time.
• Use 100% silicone sealant around any leaky areas between basin and countertop.
• For larger holes or cracks, use fiberglass mesh tape with epoxy for a more durable seal.
• If damage is beyond repair, replace the leaky sink basin completely.

Avoid using plumber's putty on sink bowls as it can deteriorate over time. When choosing a sealant, ensure it is non-porous and mold/mildew resistant once fully cured. Epoxies and polyurethanes provide the strongest, most water-tight repairs for damaged sinks. If the sink basin is severely cracked or faulty, replacement may be your only option. This may require countertop removal and professional installation.

Repairing your leaky sink is only part of the solution. To avoid recurring leaks down the road, implement these preventive maintenance tips:

• Inspect sink seals/caulk and reseal any gaps or cracks annually. Look for signs of deterioration.
• Immediately fix minor drips to prevent bigger leaks. Don't ignore small problems.
• Tighten supply lines, mounting nuts, and faucet connections regularly.
• Replace faucet washers and O-rings periodically or when showing wear.
• Upgrade old or damaged sink basins and faucets before major leaks occur.
• Have a plumber inspect/repair supply pipes and shut-off valves under sink biannually.
• Always run water into the sink when pouring boiling liquids like pasta water. Thermal shock can crack sinks.
• Avoid banging heavy pots or placing frozen foods directly into a hot sink. This can damage porcelain and enamel sinks over time.

Using a sink grid, avoiding garbage disposals which strain plumbing, and cleaning with non-abrasive products can also help prevent leaks. While drips can cause major headaches, catching any issues early and repairing leaky faucets or cracked basins right away reduces permanent damage. Contact a professional plumber if a leak is beyond your repair abilities.

Kitchen sink leaks can be prevented with proper maintenance and repairs. Quickly tackle any drips or cracks noticed to keep your sink and cabinets dry for years to come.