Home » Custom Fabrication » Water Filter Faucet Hole Drilled in a Quartz Countertop, Hudson Square

Water Filter Faucet Hole Drilled in a Quartz Countertop, Hudson Square

The kitchen had a quartz countertop with no existing faucet hole, and a new under-sink water filter system that needed one. The owners bought a Cloud RO filter and wanted the quartz core drilled for the dedicated filter faucet that comes with it. No spare hole, no knockout, nothing to reuse. The countertop was installed and the sink is undermount, so the drilling was done right there in the kitchen. Hudson Square, also called West SoHo, on the west side of Manhattan, NY 10014, New York County.

Before and after of a white quartz countertop at a sink, the spot taped and marked on the left, the installed water filter faucet on the right — *Before and after. Left, the spot taped and marked with the filter faucet lying next to it. Right, the same counter with the filter faucet standing in its own hole.*

The wood under the counter nobody knew about

A faucet hole is drilled from the top, but what decides the job is what sits under that point. So I always look underneath before I drill, to see what I have to avoid. Here that paid off. There was a wooden support under the countertop, running along the back, and nobody expected it. It was not in the photos and it was not in the plan. The brass supply fittings for the main faucet are in the same stretch too.

A tape measure under a quartz countertop running from a brass faucet supply fitting to the drilling spot, with the unexpected wooden support at the left — *Measuring under the counter from the existing faucet supply fitting. The wooden support on the left is the one that was not expected.*

I measured underneath from the existing fitting across to where the new faucet should land. The spot the owners wanted sat right beside the wood, not on it, so the hole went in alongside it and the wood was never drilled. That is luck as much as anything. Had the mark landed an inch over, the faucet would have had to move, or the wood would have had to be drilled too.

This is why I ask about it before a work day, and why I ask for a photo of the space under the counter when someone can send one. Wood under the stone is normal and drilling it is not a problem, it just has to be known before anyone marks a spot.

Masking tape with a pencil cross on a white quartz countertop, a chrome filter faucet and its black mounting nut lying beside it — *Before. The marked spot on the quartz, with the filter faucet and its mounting nut waiting next to it.*

The mark itself goes on the top as a pencil cross on masking tape. The tape is not decoration. It gives the pencil something to hold, and it keeps the diamond bit from skating on the first few turns.

Drilling engineered quartz in place

Quartz is engineered stone, ground quartz held in resin, and it is harder on a bit than marble. I use industrial diamond core bits made for stone drilling and add water to cool the bit when it needs it, not a constant flow. A finished kitchen is no place for running water across the counter. The bit starts at an angle so it bites a groove instead of sliding across the surface, then it comes upright.

I carry bits in several diameters. When a faucet shank falls between two of them, I widen the hole to fit rather than jump to the next size up and leave a loose gap around the base. The cabinets and the surroundings are covered with plastic first. Drilling makes dust and noise, there is no version of this that doesn’t, and a shop vac takes most of it.

A round drilled hole in a white quartz countertop near the sink edge, with the main faucet base behind it — *The finished hole in the quartz, next to the existing faucet.*

It is the same work as a water filter pipe hole drilled in an Ubatuba granite kitchen counter and a faucet hole drilled in a Caesarstone quartz countertop, just a different stone and a different spot.

Where my work stops

I set the filter faucet into the hole and tightened the holding nut a little, enough that it sits right and stays put. The plumbing connection is for a plumber.

The black plastic mounting nut of a water filter faucet tightened under a quartz countertop, next to a brass fitting and copper supply line — *The filter faucet mounting nut, tightened just enough to hold it in place. The connection is a plumber’s job.*

Four chrome fixtures on a white quartz countertop by an undermount sink, the new water filter faucet at the left — *After. The filter faucet standing in its own hole, next to the three fixtures that were already there.*

I offered to install the filter system when the owner first wrote, and then I took that offer back before the work day. I am a stone specialist and my insurance covers stone work, not plumbing. If a connection under a sink leaks six months later, in a building like this one the water damage goes far past the kitchen it started in, and that is not a risk I can carry. A plumber may charge more for the same connection, and part of what you pay them for is that they carry it. The Cloud kit is built for a homeowner to install and the company has a video that walks through it step by step. Here the building offered to help with the connection once the hole was there.

What to expect from a drilled hole

Here is what the owners heard before the work day:

The final diameter can come out a little bigger than marked, by about 1/16 to 1/8 inch. The faucet ring covers it.
The hole walls and the edge are not polished. Nothing shows there once the faucet is on, so polishing them is work nobody sees.
Drilling makes dust and noise. The cabinets and surroundings get covered with plastic drop cloths, and some dust still travels in the room.
The stone work is the hole. The faucet is set in place, but pipe fitting, the filter connection and any plumbing are not included.
What is under the counter can change where the hole goes. I check first, and I would rather move a faucet two inches than find out with a bit.

This building wanted a certificate of insurance before the work day. I carry general liability only, without other kinds of insurance, and the resident manager confirmed that was acceptable as long as the certificate holder and the additional insured language were right. Then I ordered the certificate from my broker. If you are in a Manhattan building, ask your managing agent for their sample COI early. That is usually what moves a work date, not the work.

Questions people ask about drilling a quartz countertop for a water filter

Can you core drill a quartz countertop that is already installed?
Yes. It is drilled in place, on the counter where it sits. An installed countertop does not come out and go to a shop for one hole.

What if there is a wooden support or a cabinet rail under the stone at that spot?
It happens, and on this job it was a surprise to everyone. Sometimes the hole fits right beside it, like here. Sometimes the wood gets drilled with the stone, which is fine, and sometimes the faucet moves a couple of inches. That is why I look underneath before I mark anything, and why a photo of the space under the sink helps before the work day.

Do I need a new countertop to add a filter faucet?
No. One hole in the right place is the whole job.

Do you install the filter system too?
No, the drilling only, and I set the faucet in its hole. My insurance covers stone work, not plumbing. These under-sink kits are made for the owner to install, and a plumber or a building handyman does the connection after the hole is there.

If you bought a water filter and your countertop has no hole for the faucet, send me a photo of the counter, a photo of the space under the sink, the faucet or its shank size if you have it, and your zip code. I’m based in Brooklyn and work in Manhattan and all over New York City. Email info@marblerestoration.us.

More about stone cutting and custom fabrication