Can anyone recommend: Plumber - required to find leak

Hi, Can anyone recommend a plumber in the Fortuna area (that speaks English as my Spanish is limited)? 

We have a water leak as there is water trickling constantly into our septic tank. We have checked the toilets, taps etc in the house and the outside toilet and nothing seems to be leaking, so we don't know where the water is coming from. We recently had our tank emptied. 

The water is constant, day and night. Thanks.  :-)