It is important to keep up your fluids in pregnancy, but should you be drinking tap water and avoiding mineral water?
Tap, mineral, purified - what's best?
In the UK, most tap water is safe to drink. UK standards for purifying general water supplies are excellent and it would be very rare to find any taps served by lead pipes anymore. (Lead used to be a danger because it leached into the water, but awareness of this over several decades has meant that pipes have gradually all been replaced.)
If you are staying somewhere where you are unsure about the safety of the pipes (for example in a very old property which doesn't look like it's been updated, or on a campsite), don't be afraid to ask the owners for more reassurance.
When travelling abroad always follow the latest Foreign Office advice on water as it might not only be dangerous to drink but also affect food preparation in the place you are visiting.
Back home, don't think that the taste is a guide. Depending on soil and other environmental factors, some area's water will be sweeter than others. In some places, the water might even be a little brown , but again, this isn't a worry if you can see that the water supply is well maintained - it's simply down to the local natural make-up of the source.
If you are still doutbful, boil and cool water for drinking or use a water jug with a good (and regularly changed) filter.
Bottled water is not always any safer to drink than your tap water. 'Pure' water still comes from the ground and may not have benefitted from things like flouridation - a process used for tap water to ensure the health of bones and teeth.
Spring water comes directly from a natural spring and is simply cleaned up to remove dirt. Mineral water comes from the ground too, of course, but can contain high levels of various minerals which can be a little too excessive in pregnancy.
There are no specific bottled waters which are banned in pregnancy and most will be fine. Their taste might make you drink more often too, if it's more pleasant to you than tap water. But given that you should be drinking a lot more water, try to drink the less 'mineral heavy' bottled waters, where possible (the mineral breakdown is printed on the side of the bottle). Evian, for example, is a good one to drink.