Thanks for the reply, I was starting to think it had something to do with the faucet since it is old and I haven't added or changed anything else, but I had no idea if that was possible.
I am a rank newbie when it comes to plumbing so if this is a stupid question cut me some slack, do you mean the washer at the end of the faucet (between screen & faucet) or inside the tap body? I haven't started to take it apart yet so I don't know what kind of valves it has inside.