Germany Doubles the Aufguss Water Limit, but Only for Saunas That Test Each Room First

Public saunas in Germany may now pour up to twice as much water per aufguss as before, if they first test the amount in the room. The change heads the revised DGfdB R 26.30.04, the guideline for carrying out aufguss in public saunas, written by a joint committee of the Deutscher Sauna-Bund and the Deutsche Gesellschaft für das Badewesen (DGfdB). The committee approved the final text in August 2025. It replaces the June 2017 edition and has been available since December 1, 2025, the DGfdB announced.

The old guide value worked out to about 1.9 to 2.9 fluid ounces of water for every 100 cubic feet of room. The new ceiling is twice the old maximum, about 5.7 fluid ounces per 100 cubic feet. In a medium public sauna of about 1,770 cubic feet, the size Germany’s accident insurers used as typical in their aufguss study, that’s the difference between about 51 and 102 fluid ounces per aufguss, or roughly 0.4 and 0.8 gallons. In a room of 20 by 20 feet with a 9-foot ceiling, the new ceiling is about 207 fluid ounces, or 1.6 gallons.

Germany has more than 2,000 public sauna facilities with about 16 million guests a year, the Sauna-Bund says, and the draft applied the guideline to every sauna not used only privately. Switzerland’s sauna association adopted the same approach in a guideline that took effect on February 1, 2026, crediting the German rule (Schweizer Sauna Bund RL 25-01).

The higher amount needs a test in each room

The extra water is allowed only after a check in the specific room to find a suitable amount, the DGfdB’s summary of the final text says. The committee has written a questionnaire for staff and guests to fill in during those tests, and the Sauna-Bund teaches the change through its academy, including a three-and-a-half-hour webinar. The full text costs €40 (about $45), sold through Sauna-Matti, and is free to the Sauna-Bund’s member businesses.

The June 2025 draft, the last full version made public, recommends on-site tests before going above the old maximum and says the results must go into the operator’s written work instructions. It lists what sets the right amount: room volume and temperature, heater size and output, the quantity and type of stones, the kind of aufguss, and the ceiling’s height and shape. Its amounts assume a room at 194°F at the measuring point above the top bench, and it says the water must never be so much that it reaches the heater’s hot parts.

The Sauna-Bund says sauna rooms have grown larger and more varied, and guests often find the old amount too little, especially at sessions billed as intense. Its surveys of guests and staff said the same, and the new values also draw on field trials with test subjects at the Donaubad in Neu-Ulm in July 2024, which local press reported involved 30 volunteers.

The draft clears the room 15 minutes before each aufguss

The committee’s 2025 description of the revision also lists a recommended entry rule, more kinds of aufguss than the classic water pour, and rules for ice balls scented with essential oils. The final wording on those hasn’t been published, so the details here come from the June 2025 draft.

Under the draft, guests are asked to leave 15 minutes before an aufguss, and the room reopens five minutes before it starts. No guest should spend more than 15 minutes in the heat, and the draft says airing the room briefly before the aufguss doesn’t change that limit. A large enough anteroom helps.

The draft lists five kinds of aufguss: classic with water, classic with ice balls, classic with water and ice, the show aufguss, and the wenik aufguss with leafy branches from the Baltic and Russian tradition. Ice counts toward the water total: the draft has staff multiply the weight of the ice by 0.92. Competition shows are outside its scope.

For staff, the draft keeps each aufguss to 6 to 10 minutes and never more than 12, with one aufguss per sauna master per working hour. Staff must be at least 18, wear clothes during the aufguss and commit in writing to the operator’s limits on water and time. Guests who ask for more must be turned down. In our report on sauna master training, Anders Hage of the Danish Sauna Masters Association warned that sustained work in high heat can exhaust staff.

Formaldehyde data stop at the old limit

Germany’s statutory accident insurers studied the air during aufguss after staff at one sauna business reported health complaints. Their study, published in 2016, measured eight rooms in five commercial saunas. Stone surfaces reached 212°F to 482°F, and water that ran down onto lower parts of the heater met surfaces up to 842°F. Formaldehyde and acetone made up most of the emissions.

With aufguss concentrate dosed to the label and poured as the DGfdB recommends, formaldehyde rose by up to 0.2 mg/m³, and all workplace limits were met. Concentrate at more than seven times the label dose pushed it to 2.0 and 2.1 mg/m³ over a 10-minute aufguss, above the short-term limit of 0.74 mg/m³. The hotter the surface the water reaches, the more formaldehyde, the study concluded. Every test pour stayed at or below the old water maximum, so the study has no measurements at the new, higher amounts.

The insurers’ guidance for aufguss staff, FBWoGes-001, still lists its February 2020 edition. It sets the old water maximum, 10 to 12 minutes per aufguss and one aufguss per staff member per hour. It also calls for at least 10 air changes an hour in the sauna room, up to 20 when needed, and for heaters built so poured water can’t hit the heating elements directly.

Hans-Jürgen Gensow, a German sauna-industry writer, questioned on his SISU Sauna Wellness Update blog whether the rule reflects real practice, especially at events, and said it isn’t clear what “health-compatible” means in medical terms (SISU).

Before you raise the water, set the room’s number in writing

The German rule doesn’t apply in the US, where a trade attorney’s white paper argued this year that operators need a standard of their own, and our operator’s guide to the business of aufguss covers staffing and costs. The German rule and its draft give any operator a working order:

• Test the amount in each room, with staff and guests, before going above the old maximum.
• Write the room’s amount and the aufguss length into staff instructions, and refuse requests for more.
• Dose concentrate to the label, and keep the water on the stones and off the elements.
• Clear the room 15 minutes before each aufguss, and keep each one to 12 minutes at most.
• Give each sauna master no more than one aufguss an hour.