The non return valve is integral to the t-piece & the pump is toward the bottom of the washer bottleNo puddling Oofo but to my surprise not too bad a spray from both sides today. Bit low and the jets won't adjust up any more, so I do suspect the pump. Mention of a non return valve is a bit worrying as I blew the pipes out and got plenty of air bubbling into the reservoir! I can't even see the reservoir so is it very difficult to get to the pump please?