As you can see here, it is a Volvo pump on the car, i'm wonder of the gasket has just failed or bolts have come loose.
And here you can just about see the water glistening at the bottom of the cover.
I've just done a quote search online with
https://www.whocanfixmycar.com and got proces ranging from £320 to £400 for a belts and pump change, no doubt they will not be quoting for an OEM pump though.