SS 304 is the commonly preferred grade for everyday kitchen sinks because it offers a good balance of corrosion resistance, durability, and cost. SS 202 looks identical when new but is generally more susceptible to staining, corrosion, and pitting than SS 304, particularly with prolonged exposure to water, salts, and cleaning chemicals. Since appearance alone cannot confirm which grade you're holding, a quick chemical spot test using a testing liquid like MOLY can help you check before installation.
Why Grade Matters More for a Sink Than for Almost Any Other Steel Item
A kitchen sink is one of the toughest jobs you can give a piece of steel. It sits in constant contact with water, detergent, acidic food residue (lemon, tamarind, tomato-based curries), and scrubbing — every single day, for years. This is exactly the kind of environment where the difference between stainless steel grades stops being theoretical and starts showing up as rust spots, dull patches, and pitting on your sink basin.
The tricky part is that a 304-grade sink and a 202-grade sink are impossible to tell apart when you buy them. They can look almost identical in shine and finish, and appearance or weight alone cannot reliably confirm the grade — weight depends mainly on thickness and dimensions, not on grade. The real difference is inside the metal, and it only becomes visible after the sink has been installed and used for a while — by which point replacing it is a much bigger job than it would have been at the buying stage.
SS 304 vs SS 202 vs SS 316 for Kitchen Sinks
| Feature | SS 202 | SS 304 | SS 316 |
|---|---|---|---|
| Nickel content | Low (nickel replaced with manganese) | ~8% (the "8" in 18/8) | ~8%, plus molybdenum |
| Rust resistance | Lower — more prone to corrosion and pitting over time | High — a reliable choice for kitchen use | Better suited to chloride/salt exposure than 304 |
| Behaviour with hard water | More prone to staining and pitting | Handles hard water well | Handles hard water and salt exposure well |
| Typical cost | Lowest | Moderate | Highest |
| Best suited for | Low-use, decorative, budget installations | Everyday kitchen sinks — the standard choice | Coastal homes, premium sinks, heavy commercial use |
In India, domestic stainless steel sinks are covered under the standard IS 13983:1994, which includes material and grade-related requirements. SS 316 is a step up from 304, mainly worth the extra cost if you're in a coastal area or want a premium, long-term installation. SS 202 is the budget option — it isn't inherently unsafe, but it's a poor match for something that touches water and acidic food every day. For a deeper breakdown of all three grades, see our complete guide to SS 202, 304, and 316.
Don't Forget Gauge — It's a Separate Thing From Grade
Buyers often confuse "grade" with "thickness," but they're two completely different specifications, and both matter for a sink.
- Grade (202 / 304 / 316) tells you what the steel is made of — this determines rust resistance.
- Gauge tells you how thick the steel sheet is — this determines dent resistance and how much noise the sink makes when you use it. Gauge numbers work backwards: a lower number means thicker steel.
| Gauge | Approx. Thickness | Feel |
|---|---|---|
| 16 gauge | ~0.060 inch (~1.5 mm) | Thickest, quietest, most dent-resistant — best for daily heavy use |
| 18 gauge | ~0.048-0.050 inch (~1.2-1.3 mm) | Standard choice, good balance of cost and durability |
| 20 gauge | ~0.036 inch (~0.9 mm) | Thin, noisier, dents more easily — avoid for a main kitchen sink |
A sink can be genuine 304 grade but still feel flimsy if it's a thin 20-gauge sheet, and it can be a thick 16-gauge sheet made from poor-quality 202 steel that will rust anyway. You need to check both — grade for rust resistance, gauge for physical durability.
How to Check Your Sink's Grade Before You Install It
Since visual inspection tells you nothing about grade, a chemical spot test is a quick and practical way to check what you're buying before it goes anywhere near your plumbing. Here's how to do it with MOLY:
- Pick a hidden test spot. Choose the underside of the sink or an edge that won't be visible once installed.
- Clean the surface. Wipe away any oil, dust, or protective film so the reagent contacts bare metal.
- Connect the 9V battery. Each MOLY pack includes the battery and connector clip — no separate purchase needed.
- Apply one drop of MOLY to the cleaned spot.
- Touch the negative (–) pole of the battery connector to the drop and hold it there.
-
Read the colour within about a minute:
- Turns black and stays black → SS 202
- Turns red and fades quickly → SS 304
- Turns red and stays red → SS 316
Doing this test at the shop counter, before you pay, is the safest time to catch a mismatch between what the seller claims and what you're actually getting. If you're still choosing a testing kit, our SS testing kit buying guide covers what to check before you buy one, and our fake vs real stainless steel guide covers the broader signs of mislabeled steel beyond sinks.
Common Mistakes Buyers Make
- Trusting the sticker or invoice alone. Grade markings can be worn off, mislabeled, or simply incorrect — verify independently.
- Judging by shine or weight. A well-polished 202 sink can look just as good as 304 on day one.
- Testing only after installation. By then, returning or replacing the sink means redoing plumbing work.
- Confusing gauge with grade. A thick sink isn't automatically a rust-resistant one.
- Assuming "premium price" means "premium grade." Branding and markup affect price as much as the actual material does — a spot test can help confirm what you're actually getting.
Frequently Asked Questions
Is SS 202 unsafe to use for a kitchen sink? SS 202 is not inherently unsafe simply because it is grade 202. However, its lower corrosion resistance makes SS 304 a more suitable choice for a sink that's exposed regularly to water, food residues, and cleaning chemicals.
What grade should I choose if I live near the coast? SS 316 is worth the extra cost in coastal areas, since its molybdenum content gives it much better resistance to salt and chloride exposure than SS 304.
Can I test the sink after it's already installed? Yes, you can still test it — pick a hidden spot like the underside near the drain if accessible, or an inconspicuous edge. It's just easier and less risky to test before installation.
Does a thicker (lower gauge) sink mean it's better quality overall? Thicker gauge means better dent and noise resistance, but it says nothing about the steel's grade. Always check both gauge and grade separately.
Will the MOLY test damage or mark my sink? No. The test uses a single small drop on a chosen spot, which you simply wipe clean with a damp cloth afterward. Most buyers test on the underside or a hidden edge to be extra cautious.
Don't guess your sink's grade — check it before you install. Test with MOLY Stainless Steel Grade Testing Liquid — available on Amazon, Flipkart, and shilpind.com — and get a quick indication of the grade before you commit to installation.
