We had this, also checked all nearby drains for bubbles when flushing - none. We researched soakaways decided ours was not functioning anymore, house 1890, new regulations would put a soak away in middle of main road, and next doors garden. We had had damp ever since lived there but only investigated after flushing the gutters and flooding side of house. Also found the old iron pipe was cemented into the underground pipe as angled too near wall. Quick solution, new Downpipes angled across wall leading to kitchen drain. Took only 2 hours Not economical or point in digging up old soak away pipes.

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