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Lindsay Scott
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Traditional flame-based cremation is currently the leading choice for Americans, surpassing the rate of burial at 53 percent of all deaths. As consumers become more aware of sustainability, interest in aquamation or alkaline hydrolysis is on the rise. This technology has been used by research industries to dispose of cadavers for over 20 years. While historically it has proven to be an effective method of disposition, green forms of cremation are still gaining traction in the funeral industry.

What is Aquamation?

Aquamation is a method of body disposition used after the death of a person or a pet. This form of water-based cremation is scientifically known as alkaline hydrolysis, and it aims to replicate organic decomposition observed in ground burials. By combining heated water with an alkali solution, aquamation accelerates the breakdown of a body into ashes. Other common names for aquamation include hydro-cremation, resomation, bio-cremation, green cremation, and flameless cremation, noting that they all refer to the same process.

Aquamation Process 

Aquamation facts

Aquamation aims to mimic and fast-track the natural decomposition of a body. The key steps of this process involve:

  • Respectful placement of the body on a metal tray inside a pressurized stainless steel chamber or vessel
  • Adding a solution of 5 percent alkali and 95 percent water to the vessel. An average of 80 gallons of liquid is used, adjusted for the weight and gender of the deceased
  • Circulation and heating of the solution from 200°F to 300°F for the duration of the process. Due to the pressured cavity of the chamber, the liquid does not boil
  • After three to four hours (or longer for lower temperatures), bodily tissues are dissolved into liquid
  • The liquid is recycled through the normal wastewater treatment facility
  • Only wet bone fragments on the metal tray remain, along with any medical implants the deceased may have had (e.g. pacemakers, hip replacements, and knee joints will come out whole). These residual fragments are free from chemicals or pathogens and are safe to handle
  • If time allows, the bones (pure calcium phosphate) are allowed to dry naturally to further reduce the carbon footprint. If the family requires the remains sooner then they are placed in a mechanical dryer
  • The dry bones are then put through a cremulator machine, which pulverizes them into a coarse white to tan powder. This is the same machine used following traditional flame cremation to produce ground ashes
  • Any remains are then provided to the family

Alkaline hydrolysis machine

While alkaline hydrolysis or “green cremation” appears to be a recent advancement in the funeral industry, the technology was first patented in 1888 in England. The initial prototype of this machine was used to dispose of animal carcasses without the use of fire. Over a century later, technology has evolved to more efficient systems that are used today.

Modern alkaline hydrolysis machines consist of a single air and watertight chamber (also known as a resomator) with a capacity of one hundred gallons. Depending on size and features, pricing can range from $150,000 to $400,000 and upwards. Basic resomator models use little pressure to control the internal temperature, resulting in slower aquamation of remains. Systems with an inbuilt pressurizer will retain heat at 300 degrees Fahrenheit and can cremate a body much faster.

How long does aquamation take?

Putting aside variables such as the size and body mass of the deceased, the average duration of aquamation is 3 to 4 hours. This assumes that modern pressurized technology is used to treat the remains. If the provider is using a lower quality alkaline hydrolysis machine, then the process can take up to 16 hours. In any case, the outcome of aquamation is the same.

What is in the water after aquamation?

As with flame-based cremation, human tissues are converted into organic compounds. Following aquamation, the residual liquid by-product known as effluent comprises a sterile mixture of salt, amino acids, soap, and peptides. No human DNA is evident in the water. The pH level of the fluid is then tested to ensure it can be expelled into wastewater. Most of the time, this solution is fairly clean and could even be used as fertilizer.

Does the deceased wear clothing during aquamation?

Burial outfit men

The deceased is usually covered in a biodegradable shroud or bag during aquamation. This can resemble coverings used in the natural burial process. As many materials will not break down during alkaline hydrolysis, any clothing worn should be protein-based (wool, silk, or leather-based) and have metal zips or plastic buttons removed.

Is a casket required for this process?

Unlike traditional cremation, a casket is not required for aquamation. This is because wood and metal materials are unable to be broken down during the process. Families who choose to hold a viewing of the body may rent a casket from a funeral provider.

Can the body be embalmed before aquamation?

Yes, this is often requested if the family plans on holding visitations or an open-casket service. The embalming fluid is broken down during aquamation as with bodily tissues.

How Much Does Aquamation Cost?

Aquamation vs cremation cost

The total price of aquamation varies between both regions and providers. On average, alkaline hydrolysis will start at $2,000 to $3,300. While this fee is higher than traditional flame cremation, the price is expected to come down as technology becomes widely available and legislated.

Aquamation versus cremation cost

The average cost of traditional flame-based cremation is between $1,100 and $2,000. While this is notably cheaper than aquamation at $2,000 to $3,300, consumers may be motivated by the environmental benefits over affordability. Savings from not having to buy a casket for aquamation may also close the divide in price between both processes.

What is the Difference Between Flame Cremation and Aquamation?


Flame Cremation

Aquamation /
Alkaline Hydrolysis

Average Cost

$1,100 to $2,000

$2,000 to $3,300


The combustible casket holding the body is placed into a cremation chamber. The chamber is heated by a furnace fueled by natural gas or propane, which reduces the body to its basic elements and dried bone fragments. The remains are ground into ashes.

Water and an alkali solution are used in a pressurized chamber containing the body. This accelerates natural decomposition, leaving bone fragments and a neutral liquid byproduct. The bone is then ground into ash.

Average Time

3 – 4 hours

1 – 3 hours


1,600 – 1,800°F

200 – 300°F

Environmental Impact




Grey coarse ash

Whiter and fine ash with 30% more volume

Key Benefits

  • Widely available

  • More affordable

  • No casket required

  • Pacemakers do not need prior removal

  • Quieter and less environmentally damaging

In deciding what approach to body disposition they should take, grieving loved ones of the deceased should consider:

Why Choose Aquamation or Flameless Cremation?

Climate change protest

In comparison to other forms of interment such as burial or flame cremation, aquamation has a much smaller carbon footprint. Further reasons for choosing water-based cremation include:

  • No release of harmful airborne emissions and mercury from dental amalgams
  • Alkaline hydrolysis uses 10% of energy consumption compared to traditional cremation which is very energy-intensive (achieving in excess of 1,800°F compared to 300°F in aquamation )
  • Aquamation does not produce methane gas. In a burial, this can seep out along with other toxic fluids and contaminate groundwater
  • Caskets are not required which limits the use of natural resources. Widespread use of aquamation could save up to 30 million tons of hardwood board annually
  • Waste by-products of the process are not harmful to the environment
  • Surgical removal of pacemakers is not required and medical implants can be recycled
  • Burial vaults in the USA use up to 14,000 tons of steel annually
  • In some regions, the availability of cemetery space is rapidly decreasing. Countries such as the UK are re-using existing burial grounds by lowering cadavers

Are the ashes different from those of flame cremation?

The ashes from alkaline hydrolysis consist of bone matter ground into a fine white to tan powder. There will be 20 to 30 percent more volume of ash retrieved during this process compared to traditional cremation, whereby flames will cause some inorganic matter to release through the air.

Ashes that are produced from flame-based cremation comprise of bone remains, casket, and clothing material. The ash is usually darker or charcoal in color due to carbon discoloration from the heat. In terms of consistency, the ashes are coarser in texture compared to those from aquamation.

Will I need a larger urn after aquamation?

Yes, you are likely to need a larger urn due to a 20 to 30 percent increase in ash volume compared to flame-based cremation. A person’s bone structure is the key factor impacting the amount of ash produced and this can be hard to estimate. An experienced provider will be able to recommend options for an urn or advise if a large container is required based on the size and body mass of the deceased.

As a benchmark to use when selecting an urn, note that the average adult will produce 3 to 9 pounds of ash. Alternatively, you can wait until the remains are provided following aquamation (usually in a container or plastic box) and choose a suitable urn after weighing.

What can be done with the ashes after aquamation?

Scattering ashes after aquamation

You are able to treat ashes produced in aquamation in the same manner as those from flame-based cremation. This may include storage at home in an urn, burial in a columbarium or niche, scattering in a significant place, creating jewelry or keepsakes with the ashes, or even dividing the remains between loved ones.

Why is Alkaline Hydrolysis Illegal?

While the benefits of alkaline hydrolysis are compelling, many states are reluctant to legalize the process for human use. This is largely due to stigma and lack of understanding about what happens to the remains – misinformed consumers believe that aquamation results in the disposal of their loved ones down the drain. Powerful lobbyists including the Catholic Church and casket-makers have also compounded this view.

In effect, this notion is false as there is no human DNA in the residual liquid produced by alkaline hydrolysis. It is also worth noting that all forms of body disposal result in a release of particles; flame cremation expels matter through the air, while in-ground burial leads to decomposition into the surroundings.

Flameless cremation states – where is aquamation allowed?

Legal alkaline hydrolysis states

Aquamation is regulated on a state level. For disposition of deceased pets, the process is approved everywhere in the United States and Canada. This is because pet crematories operate under different regulations and have adopted the practice more broadly. With growing acceptance and a reduction in technology pricing, it is expected that aquamation of human bodies will become widely available. It is currently legal in the below states and provinces:

Alabama, California, Colorado, Connecticut, Florida, Georgia, Idaho, Illinois, Kansas, Maine, Maryland, Minnesota, Missouri, Nevada, North Carolina, Oregon, Utah, Vermont, and Wyoming.

What if my state doesn’t allow aquamation?

If you are keen on using aquamation for your loved one but live in a state where it hasn’t been approved, there are still ways to say goodbye with a low carbon footprint:

  • Select an urn made out of recycled or biodegradable materials
  • Rent a casket for the funeral service and choose a cardboard container for cremation
  • Opt not to have the body embalmed. This process involves the use of toxic chemicals such as formaldehyde that are harmful to the environment
  • Some aquamation providers allow transportation from other states. They will pick up the body and provide you with ashes following the process. Depending on the costs and net environmental gain after transit, this may be an option to consider
  • Pick a funeral home that is a member of the NFDA Green Funeral Practices Certificate Program
  • Keep the ashes at home or scatter them in nature. This avoids the use of a columbarium or cremation plot that requires development and space
  • Contribute to a carbon offset fund or global warming initiative. Some crematoriums offer this as an option when aquamation is prohibited
  • Pick a crematorium that is energy efficient and minimizes toxin release with the use of a filter. Providers that are environmentally conscious are likely to recycle metals and residual materials
  • Select a burial outfit made of natural fibers for your loved one. Try to choose something they already own rather than buy new clothing
  • Do away with printed invites and funeral programs. The funeral service order of events can be projected on a screen or board
  • Serve organic food at the wake or funeral reception
  • Select a plot at a green cemetery rather than conventional burial grounds

Aquamation FAQ’s

aquamation faqs

What does lye do to dead bodies?

Lye (sodium hydroxide) is an alkali solution commonly used for aquamation or water-based cremation of bodies. When the solution is added to a resomator containing the deceased, it accelerates the natural decomposition process and sheds bodily proteins and fats. This process creates a brown liquid that can be disposed of in wastewater, while the bones and any medical implants remain intact.

Do pacemakers have to be removed from the body before aquamation?

Unlike traditional flame cremation, pacemakers and battery-operated medical implants do not need prior removal. This is a key advantage of aquamation as the body is kept intact before the process and there are no costs to retrieve the device.

Can you have a viewing and do alkaline hydrolysis?

Yes, you can. The family may decide to have the body embalmed for the viewing and conduct the alkaline hydrolysis afterward. This is no different from the option offered by traditional flame cremation.

Photo of author
Lindsay is a former funeral home director with over 23 years’ experience in the field. When she is not writing articles, Lindsay spends time with her energetic terrier and her ever-expanding brood of grandchildren.