We design and sell a complete line of DI and RO/DI hybrid water processors. So we naturally get a lot of request for information about DI material compatibility. The table below lists the most common interactions. Bear in mind that anything metallic will yield a small amount of metal back into the water until passivated, and then still smaller amounts after that. Depending on how critical you application is, be sure to perform appropriate bench-testing. Talk to your local Clean Water Crusader if you require more detailed information or design assistance.
Common Industrial Materials and their compatibility with deionized water
Material | Compatibility |
304 stainless steel | A1-Excellent |
316 stainless steel | A2-Excellent |
ABS plastic | N/A |
Acetal (Delrin) | N/A |
Aluminum | A2-Excellent |
Brass | C = Fair |
Aluminum Bronze | C = Fair |
Bronze – (85% Cu) | B-Good |
Silicon Bronze | B-Good |
Buna N (Nitrile) | A1-Excellent |
Carbon graphite | A2-Excellent |
Carbon Steel | D-Severe Effect |
Carpenter 20 | A1-Excellent |
Cast iron/Galvanized Iron/Ductile/Black Iron Pipe | D-Severe Effect |
Ceramic Al203 | B-Good |
Ceramic magnet | N/A |
ChemRaz (FFKM) | D-Severe Effect |
Copper | D-Severe Effect |
CPVC | A-Excellent |
EPDM | A1-Excellent |
Epoxy | A2-Excellent |
Fluorocarbon (FKM) | B-Good |
Hastelloy-Cr | A2-Excellent |
Hypalonr | A2-Excellent |
Hytrelr | N/A |
Kalrez | N/A |
Kel-Fr | A1-Excellent |
LDPE | N/A |
Natural rubber | A-Excellent |
Neoprene | A-Excellent |
NORYL | A2-Excellent |
Nylon | A1-Excellent |
Polycarbonate | N/A |
Polyethylene (PE) | A1-Excellent |
Polyetherether Ketone (PEEK) | SEE NOTES |
Polypropylene | A2-Excellent |
Polyurethane | SEE NOTES |
PPS (Ryton®) | A-Excellent |
PTFE | A2-Excellent |
PVC | A2-Excellent |
PVDF (Kynar®) | A2-Excellent |
Silicone | N/A |
Titanium | A2-Excellent |
Tygon | A2-Excellent |
Viton | A1-Excellent |
Ratings – Chemical Effect
A = Excellent
B = Good
Minor Effect, slight corrosion or discoloration
C = Fair
Moderate Effect, not recommended for continuous use. Softening, loss of strength, swelling may occur
D = Severe Effect, not recommended for ANY use.
N/A = Information Not Available.
Explanation of Superscript
1. Satisfactory to 72°F (22° C)
2. Satisfactory to 120°F (48° C)
Some of the questions received about this page:
Q: An Auditor questioned our use of a rubber hose and Tygon tubing for transfer of DI water in our BOD testing. Was wondering if these are acceptable?
A: Certain rubbers can add to the BOD and/or COD of the water, especially at elevated temperatures.
More importantly, when BOD is critical and the process requires in-situ disinfection, rubber interacts negatively with most disinfectants and creates a home for biofilm; so I generally advise against rubber tubing where BOD is important.
Tygon generally doesn’t impact BOD (unless bacterially contaminated) and works better with a broader range of disinfectants.
When selecting tubing, also make sure that the tubing is certified for the application at the temperature.
Q: Do have any data to indicated the expected compatibility of EPDM gaskets and 140F RO and DI Water in piping systems?
Q: Do you have any data with RO water compatibility with stainless steels at 180 F?
A: At higher temperatures, the effects of water chemistry and dissolved gases are significantly more pronounced.
As long as your purified water chloride level is <5ppm and your dissolved CO2 and O2 are low, one would not expect to see any corrosion or premature failure with stainless steel.
Q: Is cast iron pipe compatible with DI water?
A: Absolutely not, under no circumstances. Don’t even think about it!
Q: Can DI water go through galvinized (galvanized) pipe?
A: Absolutely not, under no circumstances. Don’t even think about it!
Q: What material is compatible with reverse osmosis water?
A: Think of Reverse Osmosis (R/O) water like deionized water, but with more dissolved gasses. It can sometimes be more or less corrosive than DI water, depending on site-specific chemistry. Test the water and apply appropriate caution.
Q: What about PEEK tubing, is it DI compatible?