Delta®
Cartridge - DIAMOND™ Valve - 1H
Model#:
RP50587
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PRODUCT FEATURES
Documents & Specs
Product Support, Repair Parts & Technical Specifications
Installation Information
Overall Height (in.) :
5
Valve Type:
Ceramic valve
REVIEWS
Rated 4 out of
5
by
tns1 from
Good, but a redesign could make it great
The original cartridge in my 2017 Leland kitchen faucet only lasted 2yrs before the drips started. The second cartridge lasted another 7yrs before failing the same way. Both times it took only a few minutes on the phone and Delta sent a free replacement. Kudos to them for standing by their product.
I am a bit surprised that Delta did not come up with an improvement on the RP50587, but maybe they have moved away from this cartridge on new faucets. Seven years is good, but I have seen other similar design (ceramic valve) faucets last over 20yrs without leaking.
This design uses two polished ceramic plates that slide against each other. The plates are forced against each other by the plastic case and partly by the faucet bonnet nut. When the holes in the plates line up, the water flows. When the movable plate slides far enough the holes no longer line up the water stops. On this failed cartridge there is no obvious reason for failure - the plate faces are still highly polished with no obvious scoring or wear on other moving parts - so why is it leaking?
It is possible the plates while still polished, are no longer flat and do not mate well when moved around.
There could also be tiny wear in the actuating parts that together prevent the moving plate from sliding as far closed as before.
The forces that push the plates together may have lessened over time due to aging of the plastic/rubber pieces.
Does Delta know what the failure mode is?
Date published: 2026-01-05
Rated 1 out of
5
by
LH77 from
Does not work smoothly to give you the temperature
What I hate about this faucet cartridge is that it is impossible to adjust it to the correct temperature setting. If you move it a micron to the left, it is full on hot. One micron to the right, it is full on cold. It will not easily go to the middle nor stay there. It is annoying to use at all times! I wish we could go back to springs and seals!! And it's ridiculously expensive.
Date published: 2025-12-27
Rated 1 out of
5
by
Ken_C from
Bad cartridge design - doesn't last.
I've had to replace this part twice in the past 5 years on my Delta 4353-AR-DST, and the one I put in earlier this year is already leaking again. I wish Delta would improve the design, because I hate to keep having to replace a $50 part that doesn't stand up to normal usage.
Date published: 2025-12-25
Rated 4 out of
5
by
booey from
Easy to install
Unfortunately, the product came apart when I opened the package, so it took me awhile to put it together. Once that was done, the installation was pretty easy and the video on the Delta site was helpful. The faucet now works like new!
Date published: 2025-11-18
Rated 1 out of
5
by
Disappointed customer from
Cartridges fail regularly, but cust. svc. is good
The RP50587 cartridge is just not durable. Our house was built in 2015. I am on my 4th cartridge now. Our children have moved out, so our faucet is not subjected to the heavy use a family might give it. The replacement process is not difficult, but I do not enjoy DIY plumbing work, and I bought a Delta kitchen faucet to avoid doing much maintenance. Our old house had a pre-cartridge era Delta faucet, and it was great. That said, the Delta service contacts are always very good to work with, and they ship a replacement cartridge under warranty as needed. I can’t imagine shipping all these replacement cartridges is profitable for Delta, no one wins here, the cartridge is a bad product. Our Moen bathroom fixtures do not require constant maintenance like this.
Date published: 2025-11-13
Rated 1 out of
5
by
No Stuff from
Missing partd
Here's the reason for this rating. I ordered (2) RP50587 units & only received (1). Is there a second coming?
REMEMBER
I love Delta products & all our sinks are equipped with Delta faucets.
Date published: 2025-11-09
Rated 5 out of
5
by
Duc1404 from
Universal uses in bathroom and kitchen faucet
Great product. Last long many years with minimal defects and great customer service from Delta
Date published: 2025-10-02
Rated 1 out of
5
by
Glen from
Had to replace after 9 months
It's slightly infuriating that I'm replacing another one of these after just 9 months of use since the last replacement. And nearly $50 a pop?! This is the last strike for me, next it will be a non-delta faucet replacement.
Date published: 2025-05-28
Rated 1 out of
5
by
MFGA from
Make faucets great again!
Works for a year, then you replace again
Rinse and repeat.
Dumb.
Date published: 2025-03-01
Rated 2 out of
5
by
Rick 227 from
No durability
As a contractor I have always used Delta. I have one faucet in my home and one in a customers home that use this cartridge. I have to replace the cartridge in them on average every year. I'm going change manufacturers for the lack of durability of Delta faucets.
Date published: 2024-12-19
Rated 5 out of
5
by
Mike from
anyone with minimal skill can replace
Delta quality replacement part
Date published: 2024-12-16
Rated 3 out of
5
by
PlumbGene from
Why a cartridge?
I agree with most of the reviews as my kitchen faucet has dripped from the beginning. My question is what happened to your old design of springs, rubber seal and ball for internal parts? As a plumber of 30+ years that’s why I always recommended delta. You could easily repair a drip for a few dollars buying a couple of springs and rubber seals as opposed to moen, Kohler, etc. and their expensive cartridges. Now you switched to an expensive cartridge too!? Why did you abandon a reliable, proven and inexpensive design for a more expensive version?
Date published: 2024-12-13
Rated 1 out of
5
by
Struck99 from
Develop a better cartridge
I replace this part about every other year.
When my current cartridge fails I am replacing it with a different brand faucet. This is crazy. Especially they charge almost $50 for it. I have all Delta products in my house.
Date published: 2024-11-09
Rated 5 out of
5
by
VladSI from
Original lasted 14 years
We love our Allora kitchen faucet and the Delta lifetime warranty that comes with it. The faucet started dripping until you played with the handle a bit so called support and, within 5 minutes, the cartridge and retaining nut replacement order was placed under warranty. I flushed the lines as instructed and performed the replacement... like brand new again! I hope the replacement lasts as long as the original.
Date published: 2024-10-24
Rated 1 out of
5
by
JT37 from
Doesn't Last
I purchased my home in 2015, and had to replace this cartridge three times already. The most recent one was supplied under warranty by Delta in 2022. The previous one was installed in 2019. 2 - 3 years is extremely short life for a part this expensive. When newly installed, it works well, but doesn't last long.
Date published: 2024-10-13
Rated 5 out of
5
by
SurferJoe from
So glad I read the reviews before calling Support
I love everything about the faucet and spray head, EXCEPT the seal and toggle. Calling Support for a warranty replacement.
Date published: 2024-09-29
Rated 1 out of
5
by
ticked Turky from
Replaced Cartridge Constantly!
I purchased a Delta Faucet 400-DST in the spring of 2016. This Faucet is terrible and will be replaced later in 2024! The Faucet Base & Gasket flex so much that every Cartridge is destroyed within a short period. Just glad that Delta has a Lifetime Warranty on the junk!.
Date published: 2024-08-16
Rated 2 out of
5
by
Mark from
Kitchen faucet
I need to have the cartridge replaced in my delete faucet. I went to Lowes to get one.
The price of it scared me away. Is this a warranty part if not it should be.Rp50587
Date published: 2024-08-15
Rated 1 out of
5
by
Maquis from
Cartridge/valve is expensive and not durable.
Cartridge only lasts 2-3 years. Faucet purchased in 2019. Cartridge replaced in October '21 and again in '24. Very expensive consumable; not recommended.
Date published: 2024-07-22
Rated 2 out of
5
by
Barry from
Why do I need to spend $50 every 2 years?
I have a one handle delta faucet that I paid enough, or so I thought, to get good quality. My.faucet leaked before two years were up. Now I find out that's what I should expect, a $50 cartridge every other year. Id rather have old faucets a bag of O rings laying around. This is highway robbery!
Date published: 2024-07-21
Rated 5 out of
5
by
Twincam1450 from
Delta RP 5057 IS Now improved model RP 5058
Delta RP 5057 IS Now improved model RP 5058 . They replaced mine with this model and it seems to work a lot smoother. Time will tell if it last. The real problem I am having is the poor design of the kitchen leland one handle pull down faucet. Water runs down the handle and corodes the set screw.I had to destroy the handle to get it apart with a big drill bit . It was pretty brutal easy outs didn,t work set screw was receased back in too far to use them.I used a DeWalt 20v drill and it was not easy to say the least.
Date published: 2024-06-23
Rated 1 out of
5
by
Home Fixer from
Constant Dripping
We just built a new house and this Faucet started dripping and is less than a year old. I see many others are having this same problem. Is this something you are going to or have fixed fix with an updated cartridge? We have other faucets all Pfister brand and none of them leak. Why does yours leak? All were installed the same time.
Date published: 2024-06-23
Rated 1 out of
5
by
jim F from
poorly design faucet
I bought this a few months ago and because the faucet handle is curve and not straight, it is very difficult to shut off the faucet. Delta should never have designed a handle that is not striaght. Also, the customer service department has been outsourced to Masco and you have to wait for over 30 minutes to talk to an agent. Delta should not have used this outfit who is handling over 6 different manufacturere's products.
Date published: 2024-04-13
Rated 1 out of
5
by
Mark from
Smooth action sticking and squeaking again
I have replaced this part twice and it is failing again. I called Support since it's under warranty and was put in the wait queue in position 79! Called the next day. Position 107!! Used the Virtual Assistant the next day, waited 20 minutes and my queue started going backwards!!! My email was never responded to. How does a customer get a warranty replacement from this company??
Date published: 2024-04-01
Rated 4 out of
5
by
ChuckPDX from
Dripping/failure due to installation torque?
Our 2020 kitchen remodel has main & bar sink Delta faucets that both have this cartridge, and both have failed every ~2yrs with the exact same issues reported by other reviewers: drippy, requiring fiddling with handle position/pressure to get it completely shut off.
For our last replacement, RP50587 cartridge instructions now have a new NOTICE inserted with instructions on how to properly torque the bonnet nut holding the cartridge in place to between 70-90 in-lbs (see attached clip). I used a torque wrench/socket as specified, and after several months our faucet is still operating smoothly with no hints of dripping or stiffness. Could it be that over-tightening to more than 90in-lbs during manufacture/replacement been found to cause cartridge damage and dripping??
While we otherwise really like our faucets, and although Delta support has always been helpful and honored warranty replacement quickly, I think some "get well" actions should happen here:
The "Maintenance & Installation Sheet" posted by Delta here is old (Aug2010) and should be updated to the current version with NOTICE about proper torque range. The old version only has a WARNING about not getting it securely tightened enough.
Similarly, the Maintenance section of faucet instructions that use this cartridge should be updated, instead of just that WARNING about failing to get the bonnet nut tight enough.
People getting warranty replacements should be alerted by Delta support to this torque range requirement, and instructed to pass this along if a plumber is doing the replacement.
Date published: 2024-03-22
Rated 2 out of
5
by
Kyle from
same drippy issue as everyone else
Our faucet is almost 10 years old. As others have stated, it's a constant cartridge replacement scenario. Have tried both OEM and Danco replacement as well (visually not a single difference) and it won't last more than a year or two either. But at least it's half the price, but still expensive at $23 for a part that starts to leak so fast.
Date published: 2024-03-05
Rated 1 out of
5
by
SteffCout from
Poor cartridge quantity
The cartridge failed after one year.
Date published: 2024-02-21
Rated 1 out of
5
by
jasonRF from
Failed in 6 weeks!
We purchased a new Delta Leland kitchen faucet last month. The cartridge has already failed! Reading the reviews here it is clear that we purchased a lemon. Fortunately we are still within 90 days of purchase so we are hoping to return it to the store as defective - and replace with anything but Delta. We already threw out the packaging so we will see how it goes. So frustrating!
Date published: 2024-01-27
Rated 1 out of
5
by
Constant Drip from
Tired of replacing this cartridge
Like many other reviewers on this site, my Delta faucet won’t shut off completely and I am replacing the original cartridge for the third time in 5 years. Can’t wait to replace the Delta faucet with a more reliable product.
Date published: 2024-01-25
Rated 1 out of
5
by
Jeff J from
Continue to have issues with Delta Cartr. RP50587
The last time I replaced our RP50587 cartridge was in January 2020. Delta provided that replacement cartridge. Now it is January 2024 and the same problem. Actually the cartridge has been bad for a while. I cannot remember when it went bad but I'd guess about at least 18 months ago. It does the same thing, leaks/drips unless we have the faucet handle in the right spot. Delta can we get another replacement cartridge? Thank you.
Date published: 2024-01-23
Q&A
are there installations instructions for RP50587?
Hello Gene,
Thank you for your inquiry! Yes, the Delta Valve cartridge assembly RP50587 does come with installation instructions on the back of the package it comes in. I have included the Maintenance/Installation document link, below.
https://media.deltafaucet.com/MandI/64211%20Rev%20A.pdf
Best regards,
Tanya
Date published: 2024-03-28
what is the switch on the top for ?
Thank you for your question, bill c! The switch on the top is a Handle Limit Stop, which allows you to either have the full range of motion for temperature control or to limit the handle from going to the hot side.
Best regards, Jon
Date published: 2024-03-28
All that needs replaced is the orange "O" ring on the bottom. Can I purchase these?
Hi,
We thank you for your question. The gasket on the Delta RP50587 cartridge is not a item that can be purchased separately. The entire cartridge must be ordered.
Best regards,
Brandis
Date published: 2024-03-28
this part RP50587, Diamond cartridge valve leaks. How do I take apart to repair. I have a parts #RP3614A.
Thank you for your question, David! I'm sorry for any confusion about these replacement parts and happy to clarify. The RP3614 repair kit does not fit into the DST cartridge RP50587. This cartridge is not designed to be serviced and does not have repair parts available. If this cartridge needs replaced or if you need further assistance with this repair, please contact our customer service team directly at 1-800-345-3358 Monday-Friday: 8a.m.-8p.m. EST and Saturday: 9a.m.-6p.m. EST or via email at customerservice@deltafaucet.com.
Best regards, Edward
Date published: 2024-03-28
When replacing part# RP50587, what is the best process for removing the bonnet nut? Is a special wrench required? Diffcult to tell where to loosen.
Hi Amber, Thank you for your question. The RP50587 can be removed using an adjustable wrench. The top of the bonnet nut will have the flat edges where the wrench is positioned. Here is a link to the How to replace the DST cartridge.
http://www.deltafaucet.com/shopping-tools/research/video-gallery/video.html?v=1KMlxNiWni8&cat=
Thanks,
Dave
Date published: 2024-03-28
Can you send me instructions on how to replace this psrt
Hello!
Please see the following link for an installation video for the RP50587.
https://www.youtube.com/watch?v=DxVOPo9TPTI
Please reach out with further questions!
Best Regards,
Tim
Digital Communications Specialist
Date published: 2026-03-30
I have a 9178 delta kitchen faucet and the handle is becoming hard to move and squeaks. It appears that I need a Cartridge - DIAMOND™ Valve - 1H Model#: RP50587. Is this is correct, are there any special tools I need for this project?
Hi, Steve_H!
Thank you for your question, and I am sorry to hear that you are experiencing an issue with your Delta faucet. The correct valve cartridge assembly is RP50587. You will need a 1/8" allen wrench to remove the handle assembly. You may also need an adjustable wrench to loosen the bonnet nut around the valve cartridge assembly. Please be sure to turn off the water at the shut off valve before removing the handle.
Best Regards,
Rosanna
Date published: 2024-03-28
Is this the cartridge for the 955-DST? Also, is the cartridge the same quality wherever we purchase it? We would like to buy one and replace it today.
Hello Heather,
Thank you for your inquiry! Yes, the RP50587 is the correct cartridge assembly for the Delta Victorian Pull-Down Kitchen 955-DST faucet.
All Delta faucets and parts feature the same quality parts, materials, and workmanship, no matter what kind of dealer sells them. Delta retail dealers usually sell faucets that include the handles in the boxes. Plumbing professionals and Delta Studio Showrooms sell faucets where the faucets and handles are packaged and sold separately ("LHP" models), giving the customer some additional styling choices. However, the quality of all Delta faucets and parts are the same.
Best regards,
Tanya
Date published: 2024-03-28
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