Most kitchen sink leaks don’t come from a faulty sink — they come from how it was installed. If your new sink has been dripping under the cabinet since day one, it’s almost always one of these mistakes, not a defective unit.
Mistake 1: Rushing the Cutout Fit
A kitchen sink installation in an older Singapore home doesn’t always match a newer sink’s dimensions exactly. When the counter cutout is forced to fit a sink that’s larger, deeper, or a different shape, the sink sits unevenly and puts stress on the mounting points from day one. That stress eventually shows up as a leak around the rim, even if everything looked fine when the job finished.
How to avoid it: measure the cutout against the new sink’s actual dimensions before installation day, not just against the old sink.
Mistake 2: Skipping the Pressure Test
This is the single most common cause of leaks that show up weeks after a sink installation, not immediately. A loose hose connection or poorly seated waste fitting can hold under normal use for a while before it finally gives way. A proper installation tests every connection under pressure before the job is called done — if that step gets skipped to save ten minutes, you’re the one who finds out later.
How to avoid it: ask your plumber to run the tap at full pressure and check every joint before they leave, not just a quick rinse test.
Mistake 3: Reusing Old Sealant or Worn Fittings
Old silicone sealant doesn’t bond properly to new surfaces, and worn connection hoses often get reinstalled simply because they “still look fine.” Both are common corner-cuts that lead to slow leaks that are hard to trace, since the drip location doesn’t match where the actual failure is.
How to avoid it: insist on fresh sealant and new flexible hoses as standard, not just when something looks visibly damaged.
Mistake 4: Ignoring the Drainage Angle
A waste pipe that isn’t angled correctly during installation drains slower than it should, and standing water in the trap accelerates wear on the seals — which shows up later as a sink choke as much as a leak. It’s a detail that’s easy to get wrong if the installer isn’t checking pipe fall with a level.
How to avoid it: this one’s hard to check yourself — it’s really a reason to use an experienced installer rather than the cheapest quote.
Mistake 5: Mismatched Fittings Between Sink and Tap
When the sink and tap are installed by different people, or the tap is added as an afterthought, the connector sizes don’t always match cleanly. Adapters bridge the gap but are a common weak point for leaks over time.
How to avoid it: have the sink and tap installed together in the same visit whenever possible, so the same person is responsible for both connections.
Frequently Asked Questions
Why is my new kitchen sink leaking under the cabinet?
Almost always a loose connection, poorly seated waste fitting, or a seal that wasn’t given a proper pressure test before the installer left.
How soon after installation should a leak show up if something’s wrong?
It varies — some show immediately, others take weeks as a weak connection slowly works itself loose under normal use.
Can I fix a sink installation leak myself?
Minor tightening of an accessible connection is sometimes fine, but repeated or hidden leaks usually mean the original installation needs to be redone properly rather than patched.
These mistakes aren’t unique to DIY jobs — they happen just as often when a rushed sink installation Singapore job is squeezed into a tight schedule. Taking the extra 20 minutes for a proper pressure test is the cheapest insurance against a callback.
Dealing with a leak under your sink right now? Send us a photo on WhatsApp and we’ll tell you what’s actually causing it before booking a visit.
