The current advice from the Environment Agency is that septic tanks should be emptied once a year although this can be less frequent depending on usage and on manufacturers guidelines. The reason for this frequency of emptying is that modern fully enclosed septic tank units basically settle out solids and offer little opportunity for treatment and reduction in the volume of sludge. This sludge will eventually fill the tank and overtop blocking your drainage field and potentially leading to an expensive total system failure.
Only businesses/persons registered with the Environment Agency as a waste carrier are permitted to remove and dispose of sludge from your septic tank.
Ask your contractor for the waste carriers registration number.
Use this number to check on the Environment Agency public register of waste carriers website at
https://environment.data.gov.uk/public-register/view/search-waste-carriers-brokers.
Also check that the registration has not expired.
If you have any concerns about your contractor we would advise that you use another contractor and report the incident to the Environment Agency on 0370 850 6506.
It’s worth finding a specialist Environment Agency registered contractor or company that deals with the maintenance of treatment plants and septic tanks. You’ll be able to find local professionals online or in the Local papers.
Use this search facility on the government website to search via your postcode to find a certified waster carrier.
A registered waste carrier will always provide you with waste transfer note which should be retained for your records.