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 1 out of
5
by
Daniel from
Junk
Like many other reviews, mine lasted about two years. You know how bad your product has to be to only have a 2.9 review rating? I guess they know they have you over a barrel, since it's buy another one or new faucet.
Date published: 2026-06-03
Rated 1 out of
5
by
Ledge89 from
Poor Quality Cartridge
The product quality is very poor for this particular product. The cartridge typically only lasts about a year before it starts leaking and needs to be replaced. We are on the 5th replacement cartridge so far and it needs to be replaced again after less than a year being installed. We are on city water in the Metro Nashville area and have a filter on the water line as well so the problem shouldn't be with the quality of the water. And I'm having trouble getting through to Delta customer service right now as the 800-345-3358 number is not working either. Very dissappointed in the quality of this product even with the lifetime warranty because I have to change the cartridge every year. And, according to the other reviews I've read on the Delta website, a number of other people are having the same problem. The older style product with replaceable rubber gaskets was much more reliable and easy to service.
Date published: 2026-05-05
Rated 5 out of
5
by
Athena from
Very Useful Features
I love my Leland Arctic Stainless kitchen faucet & Delta has been wonderful since I purchased it from them through Amazon in 2013. They've sent me many free replacement cartridges over the years, & even the water lines & a different spray head since then b/c I was putting up with something that I didn't realize shouldn't be happening. Evidently, this faucet has evolved since 2013 & I'm currently using a head they sent me that has 2 different types of sprays. It's time for a new cartridge under the handle b/c the spray head drips at times which is what happens when it doesn't dock properly as it's done so well in the past. Delta has evidently improved this cartridge also b/c it seems to have lasted much longer than in the past.
Date published: 2026-04-18
Rated 2 out of
5
by
TRJo from
MEH
Faucet leaks often and is hard to get it just right to shut off. Will replace cart and see if that helps. Only 4 years old.
Date published: 2026-04-17
Rated 5 out of
5
by
Hank from
Number one quality sink valve cartridge
This valve cartridge is will designed, easy to replace when it starts getting old and starts dripping. And warranted for life by Delta! Be sure to register your purchase so Delta can replace it if or when it starts leaking. Delta has a wonderful warranty and quick replacement of any of their products!
Date published: 2026-04-14
Rated 5 out of
5
by
bob27 from
Perfect example of our corporate hellscape!
What a Product! It's full of great features like cheap plastic, leaks and profits winning over quality!
Date published: 2026-03-15
Rated 2 out of
5
by
Gary from
Gaskets fail without warning.
Once again, have to contact Delta for another replacement. I think this is will be my 5th. Bad design leads to failed gaskets and the set screw for the handle doesn't line up with the replacements 🤦♂️
Date published: 2026-01-11
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
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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