is there a way to prevent unwanted creatures from sneaking in from the city sewage apart from one way valves?

Question

i have noticed through the window big rats in the ventilation ducts trying to get in the house and since my family is defenitily going to ask me to get rid of them when they are in ,,,and since they are big smelly and disgusting and probably going to release a lot of bloods which of course needs to be cleaned ,,,i thought why not figure a way out to prevent them from sneaking up the sewage pipes in the first place and then take care of the ones already in which may die soon bcz there is no sources of food, i rickon
by the way this is the first time i see rats in the house for more than 15 years which made me think that they got in through the newly connected sewage pipe to the newly constructed giant sewage system in the city
and the only protection against rats hopefully not crocs in the future is one one-way-valve

Answer 1

is there any way you can put steel wool in the openings? Using window screen wires and the steel wool the little suckers will not eat through the steel wire.
not expensive and it keeps the squirrels from my home.

Answer 2

I never heard of a one way sewer valve. Where did you find that? I think you have been watching to many horror movies.

Answer 3

hiya, if we are in a position to call streets and airports after Presidents, we are in a position to additionally call sewage plant life after Presidents! and that i will't think of of a extra installation tribute to Bush than this!:)

Answer 4

Hi,

If you can see them, shoot them.
Put down poison.
Gease the pipes.
Buy a Jack Russel terrier.
Move home.
Complain to the city health board.

Skip

Answer 5

If your drains have 'traps`, (those 'u` shaped things
that have water in the bottoms), and they are kept 'wet`,
you won't get rats that way.
They don't swim under-water.

Answer 6

a check valve may be more trouble than it is worth.