Replace it NOW!
From our Trvael log in 2009:
Another lesson learned. When the sewer hose springs a pinhole leak,
REPLACE IT. Our hose sprang a small pinhole leak the last time I used
it to dump black. As we are hooked up to sewer I thought that I would
fix it when we were unhooked and the hose had a chance to dry out. It
would be easier to work on when it was “dry”. WRONG move.
The next time I dumped black water, five days later, the pinhole was leaking so
I thought I would put my thumb over it. When I did the hose was so
brittle that it split into a long crack, black water everywhere! Shut the valve off and had to repair the hose.
It was wet, full of “stuff”, and certainly not very pleasant. The sun makes these hoses brittle, and when they spring a pinhole leak, fix it right away!.
It would have made Funniest Home Videos, watching me get out of the wayand close the valve at the same time.