Our field was failing to drain adequately about 15 years after building our house.
We had a guy come in and claim a non-permiable "bio-matt" had developed and was preventing draining. He explained it's kind of like a layer of jello.
He poked a hole through the middle of the field with a pole, pulled out the pole, and there was an immediate and loud gurgling sound as the field tried to drain into that single little hole through the bio-matt.
He then sunk a hole with the pole on a 1-foot grid and blasted it with a big blast of compressed air (little geisers erupted from each previous hole), to disrupt the bio-matt. Afterwards he installed an aeration pump in the tank to oxygenate the waste, like the waste water treatment plant does.
It's been fine ever since, 10 years or better. Costed a fraction of a new field.