Parking in Bath can be a nightmare. Free parking between Monday and Friday is virtually non-existent in the city centre, and much of the outskirts. You have to go a good 15 minutes' walk out of the centre to find a place to park free. A map of controlled parking zones can be found on the Bath NES council website 'parking permits' page.
Most of the metered parking bays in the city centre are free on weekends and evenings - check signs beside the parking spaces to confirm. Car parks are generally charged 24 hours a day, seven days a week. You can also park free on single yellow lines in the city on Sundays and after 7pm every day.
Because of the expensive parking costs (and lack of any sensible arrangement for permits for regular users), many people who come into Bath to work will park outside the centre and walk in, which means that much of the free parking space is chock-full of cars by 9am, much to the annoyance of local residents.