Pilot reported being instructed to communicate with DAB tower through the frequency 118.1 instead of the published frequency 120.7 and that it is common local knowledge to routinely use the unpublished 118.1 frequency.

Narrative

I was preparing for takeoff; and noticed that I had not heard the tower talk to the previous airplane that took off. I announced to tower on 120.7 that I was ready in sequence for takeoff; and I heard a voice (I believe from another aircraft;) 'wrong frequency.' I switched to ground; and informed them that I was ready for takeoff. They told me to contact tower on 118.1. I did that; and was cleared for takeoff; and flew to ZZZ without incident. After arriving at ZZZ; I was embarrassed about using the wrong frequency; and looked more carefully at the taxi diagram. The taxi diagram shows only 120.7 as the Tower frequency. I looked at the AFD; and again; only 120.7 listed. I checked the NOTAMs; and no mention of 118.1. I looked at the 2 approach charts for the runway; and they both list 120.7. I utilized the internet; and listened to ATIS again; and again; no mention of 118.1. I spoke to someone who regularly flies out of DAB; and he acknowledged that 'everyone knows about 118.1; but no one knows where it's listed - sometimes it's on the ATIS; and some ground controllers will mention the frequency; but to his knowledge it's written no where. If this is a commonly used frequency; why in the world isn't is listed anywhere? I was told that Daytona Tower has been using this frequency for years; and flight schools will tell students; but transient pilots are left out of the equation. If somehow I missed something; and it is indeed listed somewhere; I would love to know where I could find this; and why every other publication; lists only 120.7."