How Long Do Cremated Ashes Last?

Many people wonder how long cremated ashes last. Do they go bad? What happens to cremated remains over time? What if they come into contact with moisture - do ashes dissolve in water?

These are some of the things many families consider as they decide whether to keep the urn at home or have their loved one's remains buried in the ground.

We're going to provide answers to each of those questions.

How long do cremated ashes last?

Cremated ashes are easily preserved for a very, very long time. The cremation process breaks down the body and leaves sanitized and stable bone fragments, which do not biodegrade further. 

If you securely place the remains into a cremation urn, you can rest assured that the ashes will be stored and retained for your lifetime and beyond.

What happens to cremated ashes over time?

Ultimately, how long cremated remains "last" will depend on what you do with them. While there are many creative things to do with ashes, most families opt to scatter, bury, or keep the cremated remains at home in a cremation urn. 

Let's talk about each of those options.

Cremation Urns

Over time, cremated ashes placed into a cremation urn will... well, just sit there. The remains are placed into a plastic bag which is then put into the urn. This ensures that the ashes are very well protected.

However, even in the best conditions heat and moisture will creep in. The only damage this will do is to cause the remains to harden together and "clump" to some extent inside the urn. 


When buried, the ashes will go into an urn which will then be placed into a protective vault. That vault is buried in the ground.

Because the earth remains relatively cool, and due to the protective urn and vault, heat will have little effect on the ashes inside. Moisture can and will get in, which over time will cause the urn and vault to deteriorate and the remains to harden.


This can be done on land or in water. Some people scatter ashes from a hill or cliff, while others rake the ashes into a sandy beach or the freshly tilled soil of a flower garden bed. Still others pour the remains into a river, lake, or ocean. The tiny bone fragments and dust will be incorporated into the surrounding earth or water.

Do human ashes dissolve in water?

The "cremains" are calcium phosphates and other trace minerals left after the cremation process.

Since these do not break down further, cremated ashes will not dissolve in water but rather be swept away and dispersed by the natural movement of the ocean, lake, or river.

How long can you keep an urn at home?

Most cremation urns are designed to last for generations. Wood, marble, metal, ceramic, or glass urns will endure for many, many decades with minimal care, protecting and preserving the ashes stored inside.

The few urns that are not "made to last" are designed to aid in a green burial or scattering. These eco-friendly urns will biodegrade to return the ashes to the earth as quickly as possible.

Shop our many beautiful collections of heirloom cremation urns for ashes.