diff --git a/linkcheck/url.py b/linkcheck/url.py
index 5755cab2..0191d94e 100644
--- a/linkcheck/url.py
+++ b/linkcheck/url.py
@@ -316,7 +316,8 @@ def match_host (host, domainlist):
     return False
 
 
-_safe_url_chars = re.compile(r"^[-a-zA-Z0-9_:/\.,~;=&#%()@\?]*$")
+_safe_url_chars = r"-a-zA-Z0-9_:/\.,~;=&#%()@\?\|"
+_safe_url_chars_ro = re.compile(r"^[%s]*$" % _safe_url_chars)
 def url_needs_quoting (url):
     """Check if url needs percent quoting. Note that the method does
        only check basic character sets, and not any other syntax.
@@ -327,7 +328,7 @@ def url_needs_quoting (url):
         # handle trailing whitespace as a special case
         # since '$' matches immediately before a end-of-line
         return True
-    return not _safe_url_chars.match(url)
+    return not _safe_url_chars_ro.match(url)
 
 
 def spliturl (url):