A leaking faucet under the bathroom sink is one of those small but frustrating plumbing issues that can quickly turn into a bigger problem if ignored. If you have a Delta bathroom faucet and you’ve noticed water pooling inside your vanity or dripping from the supply lines, you’re not alone. Delta faucets are well-made, but like all fixtures, they can develop leaks over time due to wear, loose fittings, or damaged parts.
Common Causes of Leaks Under a Delta Faucet
Before grabbing tools, it helps to understand why water is leaking under the sink. Here are the most common causes:
- Loose Water Supply Connections: Over time, the hot and cold supply line connections may loosen, allowing water to drip.
- Worn Supply Lines: Flexible braided hoses eventually wear out and can develop pinhole leaks.
- Leaky Shut-Off Valves: If the valve connected to your wall pipe is worn, it may leak even if the faucet itself is fine.
- Faulty O-Rings or Gaskets: Inside the faucet assembly, seals can wear down, letting water escape beneath the sink.
- Drain Assembly Leak: Sometimes what looks like a faucet leak is actually water escaping from the drain assembly under the sink.
How to Troubleshoot the Leak
Here’s a step-by-step way to find the source of your Delta faucet leak:
- Turn off water supply: Locate the shut-off valves under the sink and close them.
- Dry the area: Wipe down all visible parts with a towel so you can clearly see where water comes from.
- Turn water back on slightly: Run the faucet and look closely under the sink for fresh leaks.
- Identify the source:
- If water drips from the hose near the shut-off valve, it’s likely the supply line or valve.
- If water appears near where the faucet meets the sink, it could be an O-ring or gasket inside the faucet body.
- If water runs from the drain area, the leak is in the drain assembly, not the faucet.
Fixing a Delta Bathroom Faucet Leak Under the Sink
Once you’ve identified the cause, here are the most common fixes:
1. Tighten Loose Connections
Use an adjustable wrench to gently tighten the hot and cold supply line nuts. Be careful not to overtighten, as this can damage threads or crush washers.
2. Replace Worn Supply Lines
If your braided hoses are old or visibly damaged, replace them. Delta supply lines are widely available and inexpensive. Always use new Teflon tape on threads when installing replacements.
3. Inspect Shut-Off Valves
If the valve itself is leaking, it may need tightening or replacement. Sometimes turning the valve fully off and back on can reseat the washer and stop a small drip.
4. Replace O-Rings or Gaskets
Delta faucets use rubber O-rings inside the spout and handle assembly. If these wear down, water can leak into the cabinet below. You can buy a Delta repair kit with new O-rings and seals and follow the included instructions.
5. Check the Drain Assembly
If the leak is actually from the drain, check the nut and gasket under the sink. Sometimes resealing with plumber’s putty or replacing the gasket solves the problem.
When to Call a Professional
While many of these fixes are DIY-friendly, call a plumber if:
- The shut-off valves are stuck or broken.
- You’ve replaced supply lines but still see leaks.
- The faucet body itself is cracked.
- Water damage is already visible in cabinets or flooring.
Preventing Future Faucet Leaks
Here are a few tips to avoid future leaks under your Delta bathroom faucet:
- Inspect supply lines annually and replace them every 5–10 years.
- Turn shut-off valves occasionally to keep them from seizing up.
- Clean mineral deposits around faucet seals to prevent wear.
- Avoid harsh cleaners that can degrade rubber seals and O-rings.
FAQs
1. How much does it cost to fix a faucet leak under the sink?
Replacing supply lines usually costs ₦5,000–₦20,000 in Nigeria for parts, plus ₦10,000–₦20,000 for plumber labour. In the US, costs range $100–$300 depending on parts and labour.
2. How do I know if the leak is from the faucet or the drain?
Dry everything and run the faucet. If water appears when the faucet is on but not draining, it’s likely the supply or faucet seals. If it appears only when draining, it’s a drain assembly issue.
3. Can I keep using my faucet if it’s leaking under the sink?
It’s not advisable. Even small leaks can damage cabinets, flooring, and cause mold growth. Shut off the water and repair as soon as possible.
4. Are Delta faucets easier to repair than other brands?
Yes. Delta offers repair kits with O-rings, cartridges, and seals that make most repairs straightforward. Their parts are widely available and designed for DIY-friendly replacements.
Conclusion
A leaking Delta bathroom faucet under the sink is usually a minor repair if caught early. Most issues trace back to loose connections, worn supply lines, or damaged seals. With basic tools and replacement parts, you can often fix the problem yourself. However, if you’re unsure or the leak persists, calling a plumber ensures the job is done right and prevents costly water damage.
By maintaining your faucet and supply lines, you’ll extend the lifespan of your bathroom fixtures and avoid unexpected leaks in the future.