Septic tank smell

[Piddy]

We are renting an old property in the Gers which has a Fosse Septique, the whereabouts of which are unknown to landlady, helpful long term neighbours etc.

During bad weather (rain-it does sometimes in the South west!) then the house fills with a very unpleasant odour. No amount of conventional septic tank treatments make any difference.

Is there a gas or odour tester available which we can easily and cheaply use to show the landlady that there is a health hazard to us and our young family and that she really needs to get it sorted.

Gas mask to the most helpful answer.

Many thanks

 

Piddy.