Get a professional in to find it - although they may not to be the cheapest, water companies tend to be honest and competent. Don't discount a faulty meter!
They are familiar with identifying the source of leaks.
As the property is rented I think the landlord should sort it out, although they may be a bit dilatory as it causes them no immediate problem. Any rectification work is almost certainly the landlords responsibility and if there is potential damage to the property it is in their interest to sort it out.
|