When to replace your breast pump parts
By The Zomee Team · Updated September 25, 2026 · 5 min read
Replace your pump's duckbill valves and diaphragms every 1 to 3 months, and sooner if suction drops. On the Mother's Nature™ W1, replace the diaphragms every 2 to 3 months.
Weak suction is one of the most common reasons moms call The Mom Line™. Worn parts and flange size are the usual causes.
Why is my pump's suction weak?
On a pump that used to work well, it's most often a worn duckbill valve or diaphragm. Replace both before you decide the motor is the problem.
On a brand-new pump, weak suction usually means flange size. Many moms need a size other than the ones included with their pump.
Flange fit can matter on an older pump too, because your size can change over months of pumping and between pregnancies. If your parts are new and the diaphragms are moving but no milk comes, measure again.
Measure the widest part of your nipple tip, not the base, and match it to the closest size. If you land exactly between two sizes, start with the smaller one.
If none of the sizes included with your pump fits, our Perfect Fit Promise™ sends you a pair in the size you need, free. The Mom Line can help you measure.
Which parts wear out?
Your duckbill valves and diaphragms need replacing most often, every 1 to 3 months. How often you pump and how you clean them decide where you land in that range. Look over these parts each time you clean your pump:
- Duckbill valves: The valve pulls milk into the bottle or milk collector and helps hold suction. With use, its opening stretches wider and suction gets weaker, so replace a valve that looks stretched or torn.
- Diaphragms: The diaphragm contracts and releases to create suction, and it helps keep milk from backing up into the tubing or motor. With use it can tear, and a torn diaphragm can leave suction weak or gone. On the Mother's Nature™ W1, replace them every 2 to 3 months.
- Breast shields: High heat can warp them. Replace a breast shield that has changed shape.
- Tubing: On the Mother's Nature H1, replace the tubes if they look worn or stretched.
Which replacement parts fit my pump?
Each pump takes its own duckbill valves and diaphragms. Check your box before you order.
The W1 includes two extra duckbill valves. The H1 and the Zomee Fit each include four duckbill valves, and the Zomee Z2 includes two, one for each side.
The Mother's Nature™ W1 Kit and the Zomee Fit Breast Shield Kit each include a duckbill valve, a diaphragm, and a milk collector for one side. The Zomee Z2 Breast Shield Kit and the Mother's Nature™ Replacement Breast Shield Kit include breast shields in the size you choose, duckbill valves, diaphragms, and tubing for both sides.
Look for these names when you order:
| Pump | Duckbill valves | Diaphragms | Kit |
|---|---|---|---|
| Mother's Nature W1 | Mother’s Nature™ W1 Duckbill Valves | Mother’s Nature™ W1 Diaphragms | Mother's Nature™ W1 Kit |
| Mother's Nature H1 | Mother's Nature™ Replacement Duckbill Valves | Mother's Nature™ Replacement Diaphragms | Mother's Nature™ Replacement Breast Shield Kit |
| Zomee Fit | Zomee Fit Duckbill Valves | Zomee Fit Diaphragms | Zomee Fit Breast Shield Kit |
| Zomee Z2 | Zomee Z2/Z1 Duckbill Valves | Z2 Diaphragms | Zomee Z2 Breast Shield Kit |
What if I see milk in the tubing?
Stop pumping right away. Milk or moisture in the tubing means a part is worn or defective, and milk could reach the motor. Call The Mom Line at 1-888-662-7159 to start a warranty claim.
On the Z2 and the H1, tubing connects the pump to each breast shield. Don't wash it. The anti-backflow design keeps milk out of the tubing, as long as the duckbill valves, diaphragms, and breast shields aren't worn or warped.
How do I clean and sanitize pump parts?
Clean the parts after every use, as the CDC recommends. Hand wash the washable parts in warm water with mild dish soap, and let them air dry completely before you put the pump back together.
For extra germ removal, the CDC recommends sanitizing pump parts at least once daily, after you clean them. That matters most if your baby is less than 2 months old, was born prematurely, or has a weakened immune system. For older, healthy babies, the CDC says daily sanitizing may not be necessary if you clean the parts carefully after each use.
To sanitize, check Zomee's care instructions first, then steam the parts in the microwave or a plug-in steam system, or boil them for 5 minutes. If Zomee's care instructions say the parts are dishwasher-safe, the CDC says a dishwasher with hot water and a heated drying cycle, or a sanitizing setting, makes a separate sanitizing step unnecessary.
High heat can warp silicone parts and wear them out sooner. If you sanitize daily, check your duckbill valves and diaphragms more often. On the W1 and the H1, remove each duckbill valve by its pull tab to reduce tearing.
Away from a sink, tools like our Breast Pump Cleaning Wipes can clean pump parts with no water. Wash the parts as usual when you get home.
Where to get help
Call The Mom Line at 1-888-662-7159 for pump, sizing, parts, and support questions. Real moms and certified lactation consultants answer it.
If a part seems defective, The Mom Line can start a warranty claim, and we usually ask for a short video of the problem. Parts are covered for 90 days.
For feeding or supply concerns, talk to a lactation consultant (IBCLC).
Questions moms ask
How do I know it's time to replace my duckbill valves?
When suction drops or the opening looks stretched or torn. Even if they look fine, replace them every 1 to 3 months.
Why is my breast pump leaking?
Leaks usually come from a worn or warped part, not the motor. Check each part for tears or warping, and replace any damaged part.
Can I put pump parts in the dishwasher?
Yes, if Zomee's care instructions say they're dishwasher-safe. According to the CDC, a cycle with hot water and heated drying, or a sanitizing setting, also takes care of sanitizing. Never put the W1's warming breast shields in the dishwasher. They're hand wash only.
Can I reuse my pump parts for my next baby?
Yes, once you check the fit and the parts. Measure again, because your flange size can change between pregnancies. Replace duckbill valves and diaphragms that were in use for more than 3 months, and any part that looks torn or warped.
Can I use a Z2 breast shield kit on my H1?
Yes. The H1 works with the Zomee Z2 Breast Shield Kit, and the Mother's Nature™ Replacement Breast Shield Kit fits both the H1 and the Z2. Order duckbill valves and diaphragms to match the kit you use.
Does insurance cover replacement pump parts?
It may. Some plans cover replacement parts, and coverage varies by plan. Call your plan's member services number to ask.
