O.k., I'm kind-a late, but there are somethings not yet said, some do help, some could help. Most of them are not expensive.

If you know where the rats come into your house, close that entrance. Rats need less than an inch to get through. So if there is
a) a gap at a door or a window,
- add some nylonbrush or a rubber lip in that area, or

b) an opening for ventilation, a window or door
- add a metal grid with a mesh size of significantly less than an inch
- where applicable also rock wool and (!) cement mortar is helpful
- in some cases also sheet metal helps to stop the rodents

c) Drains should have a metal mesh at the opening to the house to prevent the rats to enter through this channel. Also backflow traps do help.



Some domestic remedies are (they are said to help, but nobody knows for sure):

Powdered Cayenne pepper or hot chili pepper scattered about the rats' runways should help. Rats clean themselves and therefore eat the hot Cayenne pepper. It is said that they don't like that.

A limewash coat mixed with green vitriol is said to help.

It is also said that they don't appreciate the smell of camomille, cloves, mint/peppermint, oleander, and turpentine.

Used cat litter in a canvas bag put about the runways of rats is also said to help.

If you use a rat trap to catch them dead or alive, peanut butter is said to be a magic bait.


Until you have some professional help to get rid of the rats, maybe one or two of the above do help in the mean time.

Good luck.
Guido

Desktop; i7-2600k, 8 GB mem., Win 10 Pro, BIAB 2017; RB 2017 - latest build
Laptop: i5-2410M, 4 GB mem, Win 10 Pro, BIAB 2017; RB 2017 - latest build