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Alkaline hydrolysis

Alkaline hydrolysis — popularly known as water cremation — is a method of disposing of human remains using hot water and an alkaline solution to break down soft tissue, leaving only bone material that is dried and processed into a fine powder for return to the family. Scotland legalised it on 2 March 2026 under the Hydrolysis (Scotland) Regulations 2026, making it the first new statutorily-recognised disposal method in the UK since cremation under the Cremation Act 1902. It is not currently legal in England, Wales, or Northern Ireland. [source: legislation-gov-uk/hydrolysis-scotland-regulations-no1-2026-2026-05-02.html]

The process: the body is placed in a sealed pressurised chamber with water and a small quantity of potassium hydroxide (typically 95% water, 5% alkaline). The mixture is heated to around 160°C and held for four to six hours. Soft tissue dissolves into a sterile liquid; bone remains intact. The bones are then dried and processed into a white powder similar in quantity and form to cremated ashes, which is returned to the family in an urn. The liquid byproduct contains no DNA or pathogens and is released as treated wastewater. [source: legislation-gov-uk/hydrolysis-scotland-regulations-no1-2026-2026-05-02.html]

Distinguishing features against flame cremation:

  • Temperature: ~160°C (alkaline hydrolysis) vs 800–1,000°C (flame cremation).
  • Duration: 4 to 6 hours vs roughly 90 minutes.
  • Energy use: significantly lower per case.
  • Emissions: no airborne pollutants; no mercury vapour from dental amalgam; no fossil fuels burned in the process itself.
  • Implants: metal implants (joint replacements, pacemakers, dental work) survive intact and can be recycled. Pacemakers do not have to be removed in advance — they do for flame cremation.
  • Remains returned: a slightly larger quantity of whiter powder than flame cremation ashes; otherwise indistinguishable in handling.

Where it is legal:

  • Scotland — from 2 March 2026, regulated under the Hydrolysis (Scotland) Regulations 2026. Operational facilities are not yet open; providers need planning permission, a Scottish Environment Protection Agency (SEPA) discharge consent, and the regulatory authorisations set out in the Regulations. The Scottish Government estimates six to nine months from the law coming into force to first operational facility.
  • Internationally — legal in 28 US states, several Canadian provinces, the Republic of Ireland, South Africa, Australia, and New Zealand. Has been in use for over a decade.

Where it is not legal:

  • England and Wales — the Law Commission is consulting on a wider reform of funeral law that may pave the way for hydrolysis legislation. No bill has been introduced as of May 2026.
  • Northern Ireland — would require its own primary legislation; no current proposal.

Public attitudes: in the Scottish Government's pre-legislation consultation, around 84% of respondents supported the introduction of regulated alkaline hydrolysis. [source: gov-scot/alkaline-hydrolysis-consultation-analysis-2026-05-02.html]

Religious and cultural views: not yet definitively addressed by all UK faith communities. The Church of Scotland did not object during the legislative process. Faiths that traditionally require burial (Islam, Orthodox Judaism) are likely to view alkaline hydrolysis as analogous to flame cremation rather than as burial. Faiths that accept or require cremation (Hindu, Sikh, many Christian denominations) are likely to find it acceptable, but specific religious authorities should be consulted on a case-by-case basis given the novelty of the method.

→ Water cremation in the UK · Hydrolysis (Scotland) Regulations 2026

Last verified: 2 May 2026 against the Hydrolysis (Scotland) Regulations 2026 and the Scottish Government consultation analysis.