kitchen plumbing

[farrerside]

remolding an old farm house kitchen, drain and supply lines came from floor directly under sink. I am moving stub-in to the wall. With new cabinets what is the height of drain and supply lines?

[jadnashua]

Unfortuneately, that is sort of like asking how high is up...

You need to know how high the counter is (normal is around 36", but doesn't have to be). Where you place the faucet - in back, on the side, if it has attached hoses, how long they are; how deep the sink is, if you are going to have a garbage disposal, if so, what brand, etc.

Some people really like a deep sink, they can vary between 6" to over a foot. the drain needs to slope down from the sink to the wall.

[farrerside]

I was looking for a standard height for supply and drain line, new houses or new construction must have some kind of guidelines. Not every new house has cabinets installed to figure this height. I understand there are going to be variables but looking for basic starting point.

[leejosepho]

We have a typical kitchen sink set in a countertop that is 36" above the floor, and it looks to me like a drain line coming out of the wall at about 15" would work fine. If I was doing here what you are doing there, and with the 36" height considered, I would bring the drain line out no lower than 12" above the floor (which will be less from the bottom shelf of the cabinet), and the supply lines just a little higher at around 15".

[jadnashua]

If you don't choose how deep you want your sink, whether you will be using a garbage disposal, and if your faucet has attached hoses, you are risking things not fitting. Do you want to later choose a sink that will line up, or a faucet that needs extension hoses to reach the shutoffs, or do you want to choose them first and be sure everything will look great and work well. You can pick an average position, but you may not choose something that fits without pain.

[Randyj]

Recently I asked a very similar question... this is the best response I got...(from Terry): --------------------------------------------------------------------------------

Lavs
On 30" counters I used 18"

On 32" counters I used 20"

On 36" counters I used 24"
If you are a little lower than these, then you can use longer tailpieces.

Kitchens with 7" bowls, I used to use 19" on the waste and 22" on the water supply

Now kitchen sinks are coming deeper, so you will need to drop everything lower depending on the bowls.
A 10" bowl could be 16" on the waste and 19" on the water.

Of course, if you have the spec sheet with the sink, that should tell you too.

[jadnashua]

Kitchen sinks can vary by as much as 10", and then a garbage disposal can vary by 2-3" or so. Walk into a store and ask for a pair of shoes...average size. likely to be too big (you can still wear them, but they might fall off!), or be too small to actually get on...same idea with average for a kitchen. Some faucets come with attached hoses, some don't, and those that do can vary in length by 6" or so. Nothing worse than having the thing 1/4" too short. Having it 10" too long isn't the best either, but it will work. You want the shutoff valves where you can actually reach them, but still allow the hoses to reach, not back behind the sink where you can't see them to work on it or attach things. When it comes to the drain, water doesn't run uphill, so your wife loves the sink that is even 1/2" deeper than you planned...it might not drain. There are limits on the maximum height as well. Pick an average, and you may end up being stuck with something you don't want because it won't drain, or you can't reach the supply lines.

[leejosepho]

Pick an average, and you may end up being stuck with something you don't want because it won't drain, or you can't reach the supply lines.

For the record: With an emphasis on "may", "might" and/or "at least *possibly* could", I agree. In fact, and as I want to be sure I only have to do the work once, I intend to purchase our new bathroom sink and cabinet *prior to* doing the plumbing.

[jadnashua]

If you know the brand and model, you can often find the installation instructions on line. They typically show exactly where the drain and supply lines should be. take that with a grain of salt, though until you compare that with the faucet you choose.

[geniescience]

but keep in mind that there is no standard. What Jim said.

-david

[leejosepho]

... new houses or new construction must have some kind of guidelines. Not every new house has cabinets [and sinks] installed [first] to figure this height.

... there is no standard. What Jim said.

... unless you are working with something that is generally standard, of course:

On 30" counters I used 18"

On 32" counters I used 20"

On 36" counters I used 24"

If you are a little lower ... you can use longer tailpieces.

So then, and when in doubt or doing something exotic, "go a little low" if you do not know the specs and want to be safe, but be sure the trap remains above the floor and the vent is close by!