Mains Pressure Electric

You can get a good flow from a mains-pressure system (normally around 20 litres a minute) and can even get a massaging effect in the shower. 

Two different materials are used in these cylinders: ceramic-lined steel, which is often fitted with a sacrificial magnesium anode to protect the liner against corrosion, and stainless steel. 

Service life depends on local water quality, but stainless steel is likely to outlast ceramic-lined steel by a considerable margin. Ceramic-lined steel can fail after 10 years. 

The main attractions: your bath and washing machine fill quickly and you'll get a great shower. 

The main drawbacks: you may use a lot of hot water if your showerhead isn't an efficient model.