How long does it take before pid starts to damage reproductive organs permanently?

Salpingitis: The inflammation taking place in the fallopian tubes and the scarring occurring is highly variable and depends on the causative organism and the response of the particular individual affected. If you are concerned that this has created a problem with conception a gynecologist can evaluate whether your tubes have been adversely affected.

No safe interval: There's no absolutely 'safe' time period, so if you are infected (or worry that you might be) you must treat right away. Females may very quickly suffer some damage, or not at all; males rarely become infertile from chlamydia infection. Good wishes, and I hope this helps.