Water cremation

What is water cremation?

Water cremation is a gentle alternative to flame cremation. It is known by several names: alkaline hydrolysis is the scientific term, resomation and aquamation are names used by companies and providers, and you may also see bio-cremation or flameless cremation. All describe the same principle: the body is placed in a stainless-steel vessel with a solution of water and alkali, usually potassium hydroxide, sometimes combined with sodium hydroxide. Heat, pressure in some systems, and gentle circulation accelerate the natural breakdown of soft tissue.

At the end of the cycle, only the bone structure remains, along with any implants. The bones are dried and processed into a fine, white ash, which is returned to the family in an urn just as with flame cremation. Families often receive slightly more ash than with flame cremation. The remaining liquid is a sterile solution of amino acids, peptides, sugars and salts, which is typically discharged to the wastewater system under consent or, in some cases, used as fertiliser.

How does the process work?

• The body, in a biodegradable shroud or a suitable container, is placed in the vessel.
• The vessel is sealed and filled with a measured quantity of water and alkali based on body weight.
• The solution is heated, typically to between about 93 °C in low-temperature systems and around 150–160 °C in high-temperature, pressurised systems.
• After a cycle lasting from a few hours to around a day depending on the system, the liquid is cooled, neutralised if required and drained.
• The bones are rinsed, dried and processed into ash; implants are recovered for recycling.

High-temperature systems complete the process faster but require pressure vessel certification; low-temperature systems are simpler but take longer. Manufacturers differ in vessel capacity, water use per cycle, energy source and automation.

Environmental benefits

Water cremation produces no direct combustion emissions at the site, and mercury from dental amalgam remains in the vessel rather than entering the air. Studies have suggested that alkaline hydrolysis uses substantially less energy and has a lower carbon footprint than flame cremation, particularly where electricity is from renewable sources. These claims vary by system and context, so ask manufacturers for independently verified data for your conditions.

Water use is a consideration: a single cycle may use several hundred litres or more. Wastewater consent from the local utility is often required, and some authorities set limits on pH, temperature and volume.

Where is water cremation legal?

Legal status changes regularly. Water cremation for humans has been legalised in many US states and Canadian provinces, and is offered in South Africa, Mexico and Australia. In the United Kingdom and much of Europe it has been the subject of active regulatory discussion, with developments in several countries. Pet water cremation is permitted more widely. Always check current national, state and local law, and wastewater rules, before investing.

Costs and business case

Alkaline hydrolysis equipment is generally a significant capital investment comparable to, or higher than, a flame cremator, but running costs can be lower due to reduced energy use and no filtration consumables. Revenue depends on family demand; in markets where it is available, many families choose water cremation for its gentler image and environmental credentials. Funeral homes often position it alongside flame cremation rather than as a replacement.

Choosing a water cremation system

Compare manufacturers on vessel capacity including bariatric cases, cycle time, temperature and pressure range, water and chemical consumption per cycle, energy source, automation and data logging, certification for your jurisdiction, installation requirements such as drainage and floor loading, and the availability of local service. Ask for references and visit an operating facility if you can.

Specialised suppliers such as Resomation Ltd, Bio-Response Solutions and Aquamation Industries focus on alkaline hydrolysis, while some broader funeral equipment companies also distribute systems. Use our manufacturer directory and comparison tool to shortlist suppliers.

Talking to families about water cremation

Clear, respectful language helps families understand the option. Explain that the process uses water instead of fire, that ashes are returned just as with flame cremation, and why some people choose it for environmental or personal reasons. Offer the same choices of urns, memorials and ceremonies. Many providers report that once families understand it, water cremation is seen as a gentle and natural choice.

Water cremation alongside flame cremation

For most funeral businesses, water cremation is an addition rather than a replacement. Running both technologies lets families choose, spreads capacity risk and allows you to grow water cremation as awareness increases. Plan the building so that drainage, electrical capacity and floor loading support a hydrolysis vessel, even if you install it later. Staff training differs from flame cremation, particularly regarding chemical handling and pressure safety, so include it in your budget.