(1)Where a health authority have applied in writing to a statutory water undertaker for the water supplied within an area specified in the application to be fluoridated, that undertaker may, while the application remains in force, increase the fluoride content of the water supplied by them within that area.
(2)For the purposes of subsection (1) above, an application shall remain in force until the health authority, after giving reasonable notice to the statutory water undertaker in writing, withdraw it.
(3)The area specified in an application may be the whole, or any part, of the area of district of the authority making the application.
(4)Where, in exercise of the power conferred by this section, the fluoride content of any water is increased, the increase may be effected only by the addition of one or more of the following compounds of fluorine—
hexafluorosilicic acid (H2SiF6);
disodium hexafluorpsilicate (Na2SiF6).
(5)Any health authority making arrangements with a statutory water undertaker in pursuance of an application shall ensure that those arrangements include provisions designed to secure that the concentration of fluoride in the water supplied to consumers in the area in question is, so far as is reasonably practicable, maintained at one milligram per litre.
(6)Water to which fluoride has been added by a statutory water undertaker in exercise of the power conferred by this section (with a view to its supply in any area) may be supplied by that or any other statutory water undertaker to consumers in any other area ii: the undertaker or undertakers concerned consider that it is necessary to do so—
(a)for the purpose of dealing with an emergency, or
(b)in connection with the carrying out of any walks including cleaning and maintenance) by any of them.