Drains are the source of many a rat infestation. The image above is a rough plan of the drain that normally is the cause of rats escaping from the main sewer system into your home drain system.The drawing shows a drain rod entering just above the drainage channel and although your drain may not appear exactly like this when you open the inspection chamber cover, the idea is that you know where to look for the all important RODDING EYE !Houses constructed after 1955 are unlikely to have the infamous "Rodding Eye" so don't search for it if you own a young house!You will find the Rodding Eye in the last manhole on you property, usually near the roadway and usually also having a small upstanding pipe nearby with a vented cap on it (usually square box like and in galvanised metal with a grid with Mica flap behind, on the front. This is the "Fresh Air Inlet" that vents your system to stop smells. The fresh air goes into the drain at this point and exits at roof level having picked up any bad odours which are then vented out at roof level via the "Foul Air Outlet" pipe, most commonly found exiting the roof just above an upstairs toilet/bathroom.Now, these two pipes can be critical when dealing with rats. If the air vent grid on the Fresh Air Inlet pipe is broken, this will allow rats to both enter and exit your drain. Same goes with the Foul Air Outlet at roof level, however, this would more likely be an exit rather than entry point.And, why are rats able to exit the drains in your garden/yard. Because rats are widespread in our sewerage system and the only point where they are prevented from entering your private drainage set up, is through the RODDING EYE or in modern drains, through the non return flap that is on the joint where your drain joins the public sewer.Now, the Rodding Eye is a dry pipe just above the drainage channel in the last manhole on your property prior to the main public sewer (the main sewer is usually in the road outside your property).The image on this section shows drain rods into the Rodding Eye. This may not look exactly the same in your drain but essentially, you will find the Rodding Eye in the wall of the chamber immediately above the channel, just at the point it runs toward the main sewer in the road. The Rodding Eye should have an earthenware cap on it. This is to stop foul smells coming into your system from the main sewer and also to give you an access point to rod any blockage that occurs between your system and the main sewer in the road. This RODDING EYE CAP, is like a teapot lid and sits lightly cemented into the top of the Rodding Eye. Only light cement is used so that the cap can be easily removed should rodding be needed.Over time the cement softens more and any back pressure in the sewer can push the cap off. If the cap comes off it falls into the channel and can block the passage of your waste, eventually the waste water builds and begins running down the Rodding Eye instead of through its proper course. This may not be obvious when you lift your manhole/inspection cover but if there is more than 2 inches of waste water lying in the channel when you lift the cover, it is likely that the Rodding Eye Cap has blocked the pipe and you now have an open pipe to the main sewer. At this point, I will tell you that below the Rodding Eye is a "U" bend like in your home toilet, this stops rats coming into your drainage system but with the Rodding Eye Cap missing rats now have a direct route into your drains and any damaged pipes will allow them to escape either into your house or your garden.THIS IS THE NUMBER ONE POINT OF ENTRY FOR SEWER RATS TO ACCESS YOUR PROPERTY.If you find your Rodding Eye is not sealed, then seal with urgency, but remember that house built after 1955 will probably not have this system installed and these homes will rely on a small metal non return flap where your drainage pipe enters the main sewer in the road, and there is little you can do to repair that due to access difficulties.If you have rats in your system on newer properties, the use of Non-Return Valves is your best rat prevention method. CLICK HERE FOR DRAIN REPAIR PRODUCTSYou may need to poison rats in the drains and we would suggest the use of Raco Pro Blocks for this purpose. They are less likely to go mouldy than loose rat bait.If the benching is too angled to support the blocks, then you can either hang them on string from the top of the manhole or place a short board accross the benching and place/nail the rat blocks onto the board. Nailing will prevent the rats taking the blocks away and then you not knowing whether the rats have eaten the rat poison or not.
LINK TO RAT POISON PRODUCTS