True Union Check Valve

Grouped product items
1/2" Spears True Union Swing Check Valve - Slip X Slip

SKU: 207898

In stock


- +
3/4” Spears True Union Swing Check Valve - Slip X Slip

SKU: 202434

In stock


- +
1” Spears True Union Swing Check Valve - Slip X Slip

SKU: 202435

In stock


- +
1 1/4” Spears True Union Swing Check Valve - Slip X Slip

SKU: 209977

In stock


- +
1 1/2” Spears True Union Swing Check Valve - Slip X Slip

SKU: 202436

In stock


- +
2 inch Spears True Union Swing Check Valve - Slip X Slip

SKU: 202437

In stock


- +

Spears makes the highest quality True Union check valves. Use them to add a last line of defense against overflows. Check valves allow one directional water flow and are used to prevent back siphoning. They are commonly used on return pump outputs to prevent water overflowing the sump in the event of a power outage, pump failure or maintenance. These check valves feature true union fittings on each end for easy replacement and disassembly.


The golden rule of plumbing is that every job takes three trips to the store. While this can be frustrating locally it can be much much worse when shopping online. Being short a fitting or two can delay a plumbing project for days. Here are some quick tips to avoid this.

  • Plan your plumbing on paper
  • Don't skimp on unions. Unions allow for easy breakdown and maintenance as well as remove the need for precise elbow placement. Use them as often as possible.
  • When in doubt order extra. We happily accept returns for a full refund (less shipping) on all unused fittings within one month of purchase. A few extra bucks in return shipping is less frustrating than a project delay.
Write Your Own Review
You're reviewing:True Union Check Valve
Your Rating
Only registered users can write reviews. Please or

Product Questions

Are these translucent like it shows in the pics so the flap is visible?
Question by: Joe Blakley on Mar 20, 2022, 7:40 AM
Hey Joe, thanks for the question! these are translucent!
Answer by: James Johnson (BRS Staff) on Mar 23, 2022, 5:07 PM
Can these valves be installed horizontally or do they just work vertically? Thanks
Question by: Ferrell Andrews on Nov 7, 2017, 6:33 PM
The valves can be installed horizontally. You will want to make sure that the pivot of the flapper is at the top when it is installed though.
Answer by: Charlie on Nov 25, 2017, 12:54 PM
Is it measured by the inner or outer diameter of the hose?
Question by: anthony on Oct 27, 2017, 4:50 PM
Hi Anthony, thanks for reaching out!

The sizes provided for the check valves denote what size PVC pipe or spigot (slip) fitting they will work with. Plumbing sizes are nominal and do not describe the actual measurement of the pipe or fitting.
Answer by: Nick on Nov 16, 2017, 5:25 PM
What is the length of this valve?
Question by: Dr. Zoidburg on Jun 29, 2016, 12:09 PM
Great question! Here are the sizes from the manufacturer. :-)

1/2" - 4-13/16"
3/4" - 4-15/16"
1" - 6"
1-1/4" - 6-13/16"
1-1/2" - 6-1/2"
2" - 7-9/16

Answer by: Randy on Jul 1, 2016, 1:02 PM
Are the unions on this the same as any other union? For example if I were to lose or break the top screw portion of this could I substitute a union from the local hardware store's top portion and still have a good seal?
Question by: Kaietan Yankowski on May 9, 2016, 9:40 AM
Great question!
We cannot guarantee these will work with other unions. If replacement are needed we recommend selecting the same brand. Feel free to let us know if you have any further questions!
Answer by: Connor on May 11, 2016, 5:49 PM
Are there any ways to buy only the union parts? I want to take one of these from my old tank and use it with my new tank, but I don't want to buy a brand new valve just because one of the union parts is now missing.
Question by: Karl Krzyminski on Mar 9, 2016, 8:39 AM
Great question!
We do not currently have just the replacement union parts available and a full replacement valve will be needed. Feel free to let us know if you have any further questions!
Answer by: Connor on Mar 10, 2016, 3:34 PM
Can these valves be used at any angle or just vertical?
Question by: Craig on Nov 16, 2015, 11:02 AM
Why do you only offer slip fit on check valves? I'm looking at the Spears tru union 3/4". I don't want to have to glue barb fittings then if I want to hard pipe I'll have to buy a new valve,
I know they come with fpt ,better yet offer both options like the cepex ball valve.
Question by: LEROY on Aug 29, 2014, 10:24 AM
Hi Leroy,

I apologize for not having a threaded option for you. I have not seen the clear swing check valves with threaded unions but if our supplier has them I will suggest we carry them in the future.

For now you can always add a pipe adapter to them to make them threaded.

I hope this helps!
Have a great day :)
Answer by: Bulk Reef Supply on Aug 29, 2014, 10:24 AM
My return from sump to display tank is 3/4" clear tubing. Would this product be best to prevent back siphoning?
Question by: Becky on Jun 22, 2014, 5:00 AM
Hi Becky,
This product would work just fine for that purpose. Just keep in mind that the fittings on this valve are slip fittings (for PVC pipe) so you will want to glue in a pair of barb adapters like the ones linked below so that you can use it with your flexible tubing.


Answer by: Bulk Reef Supply on Jun 22, 2014, 5:00 AM
Will this 1" fit on reg white 1" pvc ?
Question by: Shannon on Jun 21, 2014, 12:17 PM
Hey Shannon,
It sure will!
Answer by: Bulk Reef Supply on Jun 21, 2014, 12:17 PM
Do you guys recommend placing these in the return lines routinely? How much will they decrease the flow back into the tank due to increased resistance in the return line? Thanks!
Question by: Sean on Apr 27, 2014, 4:57 PM
Hi Sean,
The best thing to do would be to set your system up so there it is not a problem if there is no check valves (so you have enough room in the sump to handle the water). Then if you want to, you can add check valves for convenience if you like (you will have less issues like skimmer overflows if the sump doesn't fill with a bunch of water every-time the power goes out). They will have a bit of an effect on your flow but for the most part its not something you would notice with the naked eye.
Answer by: Bulk Reef Supply on Apr 27, 2014, 4:57 PM
To piggyback on Richard's question. I'm using the braided vinyl for my return with the CPR return. I need to get a check valve in there as well. So with this valve would I be able to use PVC cement to attach it in my vinyl line? Or would I be able to use more ratcheting clamps? Just need to know how I can get a check valve in there safely.

Question by: Andres on Jan 20, 2014, 7:56 AM
Hi Andres,
These check valves come ready for rigid pipe. In order to use flexible tubing you would need to first glue in a barb fitting, for example the street x barb fitting. From there you can put your braided tubing over the barb and secure with ratchet clamps.
Answer by: Bulk Reef Supply on Jan 20, 2014, 7:56 AM
Does this check valve attach to pvc pipe or flexible tubing? If pvc are the connections threaded or smooth?

Thank you.
Question by: RICHARD on Oct 2, 2013, 4:29 PM
Hi Richard,
The check valve is a slip connection for pipe (which would be smooth).
Answer by: Bulk Reef Supply on Oct 2, 2013, 4:29 PM