Words in s. 21(1) substituted (1.4.2016) by Water Act 2014 (c. 21), s. 94(3), Sch. 7 para. 29(2)(a); S.I. 2016/465, art. 2(m), Sch. 1 para. 1(j) (with Sch. 2) (as amended (22.3.2017) by S.I. 2017/462, art. 16)

Word in s. 21(1) substituted (1.4.2016) by Water Act 2014 (c. 21), s. 94(3), Sch. 7 para. 29(2)(b); S.I. 2016/465, art. 2(m), Sch. 1 para. 1(j) (with Sch. 2) (as amended (22.3.2017) by S.I. 2017/462, art. 16)

Word in s. 21(2) substituted (1.4.2016) by Water Act 2014 (c. 21), s. 94(3), Sch. 7 para. 29(3); S.I. 2016/465, art. 2(m), Sch. 1 para. 1(j) (with Sch. 2) (as amended (22.3.2017) by S.I. 2017/462, art. 16)

http://www.legislation.gov.uk/ukpga/1991/56/section/21Water Industry Act 1991 An Act to consolidate enactments relating to the supply of water and the provision of sewerage services, with amendments to give effect to recommendations of the Law Commission.1991-07-25texttext/xmlenStatute Law Database2026-09-23Expert Participation2026-09-14Water Industry Act 1991Pt. 3 Ch. 2BWater Act 2014s. 12s. 94(3)Water Industry Act 1991s. 17A(2)(ba) and wordWater Act 2014Sch. 5 para. 4(2)(b)s. 94(3)Water Industry Act 1991s. 17A(c)Water Act 2014Sch. 5 para. 4(2(c)s. 94(3)Water Industry Act 1991s. 17A(d)Water Act 2014Sch. 5 para. 4(2)(c)s. 94(3)Water Industry Act 1991s. 17AA(1)(ba)(bb)Water Act 2014Sch. 5 para. 5(2)s. 94(3)Water Industry Act 1991s. 17BA(5A)Water Act 2014Sch. 5 para. 7(3)s. 94(3)Water Industry Act 1991s. 17HA(9)(b)(ia)Water Act 2014Sch. 5 para. 16(2)s. 94(3)Water Industry Act 1991s. 23(2AA)Water Act 2014Sch. 7 para. 35(4)s. 94(3)Water Industry Act 1991s. 23(8)(9)Water Act 2014Sch. 7 para. 35(10)s. 94(3)Water Industry Act 1991s. 95ZA(6)Water Act 2014Sch. 5 para. 39(4)s. 94(3)Water Industry Act 1991s. 96ZA(2)-(5)Water Act 2014Sch. 5 para. 40s. 94(3)Water Industry Act 1991s. 106B(3A)Water Act 2014Sch. 7 para. 94s. 94(3)Water Industry Act 1991s. 117G(2)(aa)Water Act 2014Sch. 5 para. 41(2)s. 94(3)Water Industry Act 1991s. 117G(4)-(4D)Water Act 2014Sch. 5 para. 41(3)s. 94(3)Water Industry Act 1991s. 117G(6)(aa)Water Act 2014Sch. 5 para. 41(4)s. 94(3)Water Industry Act 1991s. 117K(2)(aa)Water Act 2014Sch. 5 para. 42(2)s. 94(3)Water Industry Act 1991s. 117K(5)(5A)Water Act 2014Sch. 5 para. 42(3)s. 94(3)Water Industry Act 1991s. 117L(9)Water Act 2014Sch. 5 para. 43(3)s. 94(3)Water Industry Act 1991s. 117N(4)(aa)Water Act 2014Sch. 5 para. 45(2)s. 94(3)Water Industry Act 1991s. 117N(8)(aa)Water Act 2014Sch. 5 para. 45(3)s. 94(3)Water Industry Act 1991s. 117N(11)(aa)Water Act 2014Sch. 5 para. 45(4)s. 94(3)Water Industry Act 1991s. 117O(4)(aa)Water Act 2014Sch. 5 para. 46(2)s. 94(3)Water Industry Act 1991s. 117O(8)(aa)Water Act 2014Sch. 5 para. 46(3)s. 94(3)Water Industry Act 1991s. 117S(7)-(9)Water Act 2014Sch. 5 para. 49s. 94(3)Water Industry Act 1991s. 177K(7)(aa)Water Act 2014Sch. 5 para. 42(4)s. 94(3)Water Industry Act 1991s. 207D and cross-headingWater Act 2014s. 39s. 94(3)Water Industry Act 1991s. 207D(5)Water Act 2014Sch. 5 para. 52(a)s. 94(3)Water Industry Act 1991s. 207D(5)Water Act 2014Sch. 5 para. 52(b)s. 94(3)Water Industry Act 1991s. 213(1ZA)Water Act 2014Sch. 5 para. 53s. 94(3)Water Industry Act 1991s. 213(1ZA)Water Act 2014Sch. 7 para. 119(3)s. 94(3)Water Industry Act 1991s. 119(2)(ab)Water Act 2003s. 89(1)(a)s. 105(3)Water Industry Act 1991s. 119(3)Water Act 2003s. 89(1)(b)s. 105(3)Water Industry Act 1991s. 121(1)(ba)Water Act 2003s. 89(2)(a)s. 105(3)Water Industry Act 1991s. 39E-39HEnvironment Act 2021s. 78(7)s. 144s. 147(3)(4)Water Industry Act 1991s. 141DCEnvironment Act 2021s. 83s. 144s. 147(3)Water Industry Act 1991Pt. 4 Ch. 5Water (Special Measures) Act 2025s. 4(2)s. 17(3)(b)s. 17(4)(b)Water Industry Act 1991s. 2(4A)(4B)Water (Special Measures) Act 2025s. 10(a)s. 17(3)(d)s. 17(4)(d)Water Industry Act 1991s. 87(7C)-(7F)Health and Social Care Act 2012s. 35(6)s. 306(2)(3)Water Industry Act 1991s. 17(2)(aa)The Competition (Amendment etc.) (EU Exit) (No. 2) Regulations 2019 (expired—not approved)reg. 21reg. 1(1)Water Industry Act 1991s. 17R(2)(aa)The Competition (Amendment etc.) (EU Exit) (No. 2) Regulations 2019 (expired—not approved)reg. 21reg. 1(1)Part II APPOINTMENTMENT AND REGULATION OF UNDERTAKERS CHAPTER II ENFORCEMENT OF INSOLVENCY Enforcement orders
21 Validity of enforcement orders.(1)

If the person to whom an enforcement order relates is aggrieved by the order and desires to question its validity on the ground—

(a)

that its making or confirmation was not within the powers of section 18 above; or

(b)

that any of the requirements of section 20 above have not been complied with in relation to it,

the person may, within forty-two days from the date of service on it of a copy of the order, make an application to the High Court under this section.

(2)

On any such application the High Court may, if satisfied that the making or confirmation of the order was not within those powers or that the interests of the person have been substantially prejudiced by a failure to comply with those requirements, quash the order or any provision of the order.

(3)

Except as provided by this section, the validity of an enforcement order shall not be questioned in any legal proceedings whatsoever.