Just as you create surveys you can easily delete them again.
Deleting surveys can only be done from the archive. Therefore you have to archive the survey first, before deleting it in the archive.

To delete a survey please proceed as follows:

Navigate to the overview
Click on the checkbox in front of the survey you want to delete and go to the bottom of the page
Check the marked surveys checkbox and click the archive button
Select the go to archive button and on the left you can tick the checkbox of the survey you want to delete
Navigate to the bottom of the page and tick the checkbox of the marked surveys
Now click the delete button next to it

Attention
We do not keep a copy of the surveys. If you delete a survey it will be permanently deleted including all associated data (questions, elements, settings and results).
If you delete a survey that is saved as a template you delete only the survey not the template. The template is still available.