My kitchen sink is at the end of the water supply run. Bath tub comes first,
then bathroom sink, and finally, the kitchen. The water pressure in the
bathroom is fine, but it's bordering on anemic at the kitchen faucet. It's a
brand new Moen, and the same problem existed before I installed the faucet.
I wonder if the reason is that in the supply line, after the bathroom but
before the kitchen, there are shutoffs - the lever type that you turn 90
degrees to operate. Does that type have any sort of bad reputation for
messing with pressure, as compared to the knob type that requires several
revolutions to open or close?
OK. Thinking just of the cold water for the moment, the supply line is a
straight run from the meter to the kitchen, with branches picked off about
20 feet back for the bathroom. It takes a 90 degree bend upward to the
kitchen sink one floor above. When I replaced the faucet, I also replaced
the flexible supply lines because they looked worn, but the problem remains.
What's your next guess?
Can the shutoff be taken apart? If so I would pull out the stem and
take a look at it.
You could do a test at that point too. Someone hold a pail under it
while turning on the water supply. I would really expect the lever type
to give better flow but there could be something stuck inside.
More than likely the water lines in the home are to small. The only
unpractical solution is to replace all the water lines and fittings to
This is the problems in most new homes, more economy, cheaper
Master Ground Water Contractor
A minimum of 1/2" but personally I like 3/4" lines. Usually the line
coming in from the meter is 1" to 1-1/4". Why does the builder install
3/8" (or smaller lines) in the home. Because it's cheaper.
Search Google for "Porky Cutter" for more about Porky!
Porky Cutter, MGWC
But, the pressure's fine in the bathroom. The next stop is the kitchen,
which is just 18 feet more pipe, in terms of distance. And, my outside hose
faucet has loads of pressure, and the longest pipe run (from the meter). All
the same size pipe.
It is true that the type of valve has no bearing on the water pressure,
however it does have a bearing on flow rate which most people perceive
The ball valve type (1/4 turn lever, or some new knob types) provide a
straight through flow path that provides far less flow resistance than
the multi turn knob type where the water has to take typically two 90
degree turns. In short the 1/4 turn ball valve type are superior to the
multi turn type.
I'd suspect that there might be a flow limiting washer on the faucet.
I've seem them just above the aerator, a metal washer with a small hole
in it, that limits how fast water can come out. I throw them away. I
like to be the one that controls the flow of water, not some pencil
necked geek in a government office regulating what faucet manufacturers
must add to their products.
Doug, if you hooked up a hose to the shut off valve under the sink, how
long will it take to fill the can? This will eliminate the new fixture
and start locating the trouble. Could be there's a restriction in the
water pipe between your bathroom and kitchen. If perhaps a upstream
valve decided to come apart some time ago, a piece could be caught in a
downstream elbow or at the shut off valve itself. How easy would it be
to replace the shut off valve. Do you have the same flow rate problem
with hot water too?
If you're going to replace them, put in the ball valves. They are only
there to turn it on or off, so you might as well get the maximum flow.
You'll regulate the actual flow at the faucet. I'll just bet you find
some blockage upstream of the valves, if not at the valve itself. IME,
even the water company doing some repairs can introduce contaminates
into the water supply, and its just your "bad luck."
Solder a male 1/2" threaded nipple to the end or use a drop ear with a close
nipple. Most valves come with 1/2" female threads so you can change in the
future without soldering. Don't forget to flush the pipe while the valve is
removed. If still slow, try probing with a bit of #14 copper wire
Regardless of the amount of valve opening, Static pressure will be equal at
both sides of the valve when no water is flowing.
While the water is running, the Dynamic water pressure will be reduced by
the amount the valve is closed (impedance).
It's just like voltage across and current through a resistor.
Multi turn valves allow more control over dynamic pressure but have
reliability issues with being turned all the way off. Ball valves (lever or
knob) turn all the way off and on better but have less control in the middle
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