Adding an Additional Check Valve Between Fresh Water Tank and Shurflo 4008 Water Pump
Updated 09/02/2025 | Published 08/04/2025
Products Featured in This Question
Question:
I would like to add a 1/2inch inline check valve to the water line between the fresh water tank and my Shurflo 4008 water pump as a backup to the integral check valve in the pump. The ports on the pump are not tapered threads. I think they are probably NPSM threads. All of the inline check valves I have been able to find, including those on etrailer.com, have tapered threads. Are there check valves available that are compatible with the thread on the Shurflo pump?
asked by: Peter
Expert Reply:
Hey Peter, thanks for reaching out!
It looks like all of the check valves we carry use the NPT type of tapered threads, but we still might be able to make this work.
If you're able to modify your water line at all, you can then install a check valve like the B&B # BM38GR or the Camco # CAM23303 depending on what fittings you use. This will add more potential fail points to the water system, but it's going to be your best bet to adding another check valve when your water pump has a unique thread style.
What kind of water line do you have between the fresh water tank and your pump?
Product Page this Question was Asked From
B&B RV In-Line Check Valve - Black
- RV Fresh Water
- Prevent Backflow
- Valves
- Plastic
- Check Valve
- 1/2 Inch
- Threaded
- B and B Molders
more information >
Continue Researching
- Search Results: rv door window shade
- Search Results: water line connection rv fresh water
- Search Results: rv water heater accessories and parts
- Search Results: hose clamps
- Search Results: accessories and parts
- Shop: Seaflo Accumulator Tank for RV and Boat Water Pumps - 0.75 Liter
- Q&A: Best Air Bag Kit Compatible with B and W Turnoverball Hitch for a 2002 Ford F250 4x4 Long Bed
- Search Results: seaflo rv water pump
- Search Results: accumulator tank rv water pump
- Shop: B&B RV In-Line Check Valve - Black
- Shop: Kenda Karrier KR35 ST225/75R15 LRD Radial Trailer Tire w/ 15" Black Mod Wheel - 6 on 5-1/2
- Shop: Valterra Hose Clamp - Stainless Steel - 3/8" to 7/8" Diameter - Qty 1
- Shop: B&B Dual RV Water Inlets - City Water and Gravity Fill - Plastic Check Valve - Polar White
- Video: Seaflo Accumulator Tank for RV and Boat Water Pumps: The Breakdown
- Shop: Replacement 17-rpm Lift Motor for Dometic FanTastic B Series Roof Vents w/Powered Lifts - Off White
- Shop: Replacement Lift Arm for Dometic FanTastic Roof Vents
- Video: An In-Depth Look at the Seaflo Accumulator Tank for RV and Boat Water Pumps
- Q&A: Axle Seal Replacement for AL-KO T52 Trailer Axle
- Q&A: Hub and Drum Assembly for AL-KO T-52 Axle
- Video: An In-Depth Look at the B and B RV In-Line Check Valve
- Q&A: Looking For Replacement Backflow valve For 2018 2018 Keystone Outback 332fk
- Article: Trailer Wiring Diagrams
- Q&A: Lug Nut Torque Chart for Trailer Wheels
- Shop: Trailer Hitch
- Shop: Trailer Wiring
- Article: How to Measure for Trailer Hitch Drop
- Q&A: Comparing Kenda KR03, KR35, And KR53 Tires
- Q&A: Best Suspension Upgrade for 33" Tandem Axles: Road Armor vs Dexter EZ Flex for Ember 22ETS
- Video: Hands-On with the Hub Saver Hub and Wheel Protector
- Article: Wiring Trailer Lights with a 7-Way Plug (It's Easier Than You Think)
on RV Fresh Water
Jon G.
9/2/2025
Hey Peter, did you find a way to modify your water line to install the check valve? I'm asking because your experience could help others facing the same issue with unique thread styles on their water pumps.