A friend has a house in the countryside, built about 6 years ago. The septic tank is the plastic bulbous type as far as I can remember. In the general area of the tank are 3 manholes, two of which are in line with ducting carrying waste from the house. They are about 18 inches in diameter. The third is beyond these two and is a vertical concrete 9 inch pipe, located roughly at right angles to the line of the other two. To the right are 3no. 4 inch upstands with vent covers. All 3 manholes presently contain effluent to a depth of about 12 inches from the surface of the ground. When a toilet is flushed in the house the effluent backs up in an inspection chamber near the house and gradually flows away. There is evidene of solid deposits in this chamber. We have contacted the Department of the Environment seeking to have the tank emptied but their reply is that the system needs rodded rather than emptying. Rather a long post but I wonder if anyone can advise if the DOE is correct. I can see no sense in rodding when all effluent in the vicinity is at the same high levl. Thank you for any assistance.
Get it emptied by a local independent company. We have one and find the local people to be cheaper, friendlier and more knowledgeable than the local authority. Sometimes they subcontract to the same guys anyway.
It definitely needs emptying and the person who empties it will help diagnose any problems. If you can tell us where they are roughly i would happily google to find a similar service to the ones I use.
It does sound as though the tank needs de-sludging. Emptying it will then show up any blockages.
It may well be that the soakaway (outlet) is blocked. Either way, emptying would be the first thing to consider.