Hydrolysis is a process where sole units separate or degrade due to a build-up of moisture within the sole unit. Sole units will degrade when your footwear is used only occasionally and is stored for long periods of time.  

How Does Hydrolysis Happen?

Hydrolysis occurs if boots are exposed to: 

  • Harsh chemicals 
  • Manure (e.g. from dairy farms) 
  • Lack of wear (most common) 

If the boots are left sitting (without use) for long periods of time, moisture builds up within the sole unit.  

Without wear, this moisture is unable to be dispersed and eventually, this build up of moisture causes bacteria to attack the PU midsole. This causes the midsole disintegrate/crumble away.  

When a PU midsole begins to deteriorate, you'll see small cracks along the injection area, above the sole unit. This is an indication that your boots are wearing out. 

Over time, this disintegration will cause the sole unit to come clean away from the boots.  

Warranty For Hydrolysis

Hydrolysis is not a warranty or manufacturing fault; it occurs in all LOWA boots with PU midsoles. 

Hydrolysis is a normal material ageing process that occurs in all footwear with a cushioned PU midsole independent of the manufacturer.  

The process also occurs in automobile, tires, ski boots or helmets and does not represent lower quality or a quality issue in materials or workmanship. 

Why Does LOWA Use PU Midsoles?

There are two types of midsole cushioning sole injection technology popular with outdoor boots: EVA and PU.  

LOWA uses PU Injected Technology, because of its superior attributes to extend the life of their boots. Typically, more than 2.5 times more than EVA. 

PU midsoles are a terrific shock absorber, rebound well, and will last longer on the trail. 

A PU midsole also doesn't deform under heavy pack loads as a regular EVA midsole would.

What If I've Taken Good Care Of My Boots?

Hydrolysis happens regardless of where your boots are stored (even if you have stored them in a cool, dry place away from sunlight and taken good care of the boots with appropriate care product). 

Sole units will degrade faster without use than if the footwear is worn regularly. This is why it is important to regularly wear your LOWA boots.  

How To Delay Hydrolysis

To avoid early onset hydrolysis, wear your LOWA boots at least once every 2-3 months to keep up frequent usage.

It is as easy as going for a stroll around the block, taking the dog for a walk, or wearing them around at work! 

This will reduce the amount of time the boots are stored and the chances of the PU midsole disintegrating prematurely. 

Did you know, by keeping your boots on your feet and out of the storage shed, you will get two to five times the performance life compared to moulded EVA midsoles?  

Regular usage of your LOWA’s will ensure your boots last for a long time.

The Solution

If your boots qualify for a resole, the entire sole unit can be replaced when hydrolysis occurs.  

You can find out more about the resoling process and submit a resole form by clicking here. 

Note: If your boots have shown pre-mature hydrolysis (I.e., less than 6 months), or you believe your case is different, please either: 

  1. Fill out our online Warranty & Repair form if you purchased the boots from our website. 


  1. Head into the authorised LOWA retailer from where you purchased the boots, and a staff member can help you out. 

To ensure your boot soles can be resoled, you can purchase boots with a resolable outsole. Just look for a resole icon like this! 

Where Can I Find More Information?

All boot care and warranty information are included in the paperwork provided inside the boot box packaging when the boots are purchased as well as on our website.  

You can read more about LOWA’s 5 reasons to care by clicking here. 

You can also read more about LOWA’s warranty and repair policies by clicking here.