Undermount Single Bowl Black Onyx Granite Kitchen Sink - Deep Single

Our review of the KRAUS 31 in Undermount Single Bowl Black Onyx Granite Kitchen Sink finds it well suited for homeowners who want a durable, visually striking sink with an integrated disposal kit. The single biggest reason to consider this model is that it bundles a high-performance 3/4 HP continuous-feed garbage disposal with a deep, extra-deep granite composite basin, delivering a one-stop upgrade for a busy kitchen where capacity and waste handling matter. It is a practical choice for cooks who need a roomy, low-maintenance sink and a powerful grinder included out of the box.

Key Features

• Extra-deep basin: The 9 1/4 in depth and gently rounded corners provide generous capacity for oversized pots and make rinsing easier.
• Granite composite: Made from 80% natural quartz and acrylic resin, the surface resists heat and hides everyday wear while feeling like real stone.
• Included WasteGuard disposal: The 3/4 HP MagnaGrind motor runs at 3800 RPM for faster operation and handles large quantities of food waste continuously.
• Easy-install EZLock system: The 2-step mounting assembly and stainless steel rim allow straightforward undermount installation without plumbers putty in many cases.
• Complete installation kit: The package includes basket strainer, drain and dishwasher connectors, power cord, stopper, mounting flange and a kitchen towel for immediate setup.
• Sound-absorbing surface: The non-porous granite composite dampens noise and is simple to wipe clean after heavy use.

Who It's For

This sink is best for homeowners and renovators who want a single, deep bowl for washing large pans, soaking dishes, and handling heavy prep tasks, combined with the convenience of a bundled garbage disposal. The included 3/4 HP continuous-feed unit suits busy families and anyone who prefers quicker, continuous grinding over batch-feed models.

Those who should look elsewhere include buyers needing a double-bowl layout or a different material finish; also, shoppers requiring a disposal with an air switch (sold separately) or specialized commercial-grade grinding beyond residential capacity should evaluate other options.

Pros & Cons

Pros

• Deep, spacious bowl makes washing large cookware easier and increases usable workspace.
• Durable granite composite resists heat and hides everyday marks while remaining easy to clean.
• Powerful 3/4 HP MagnaGrind disposal provides fast grinding and continuous-feed convenience.
• Complete kit simplifies installation with useful accessories included.

Cons

• Some customers report occasional shipping damage to edges, so careful inspection on delivery is advisable.
• Color and speckle pattern may vary slightly from photos, which can affect matching to other finishes.

Specifications

Outer sink dimensions	30 1/2 in L x 17 in W x 9 1/4 in D
Minimum cabinet size	33 in
Drain opening	Standard 3 1/2 in round
Garbage disposal	3/4 HP MagnaGrind, 3800 RPM continuous feed
Disposal grinding chamber	40.6 oz
Installation clearance (disposal)	Minimum 10 1/4 in
Material	Granite composite - 80% natural quartz with acrylic resin

Our Verdict

The KRAUS Black Onyx undermount single bowl is a strong value for homeowners who need a deep, low-maintenance sink plus a powerful disposal without sourcing parts separately. It combines robust granite composite construction with a fast 3/4 HP MagnaGrind motor, making it a sensible upgrade for busy kitchens where capacity and reliable waste removal matter.

Frequently Asked Questions

Does the kit include a drain assembly?
Yes, it includes a basket strainer drain assembly, stopper/plunger and drain and dishwasher connectors.

What type of disposal is included?
The kit includes a continuous-feed 3/4 HP WasteGuard disposal with a 3800 RPM MagnaGrind motor.

Is the sink heat resistant and easy to clean?
Yes, the granite composite surface is heat resistant, non-porous and designed to be simple to wipe clean.