Can Aluminium Fittings Be Used in Drinking Water Systems?

The short answer is no — and the reasons are worth understanding clearly, because aluminium is often considered for water applications on weight and cost arguments, without the regulatory and health picture in view.

Aluminium alloys are not among the metals accepted for pipes and fittings in contact with drinking water in the EU, and aluminium-bodied plumbing fittings are practically absent from the approval listings of the UK, the USA and Australia. This is not an oversight — it follows from the material's corrosion behaviour in drinking water and from the limits that water suppliers have to meet for aluminium at the tap.

The Health Concern

Aluminium in drinking water has been studied extensively: it is the third most abundant element in the earth's crust, occurs naturally in some sources, and aluminium salts are used as coagulants in water treatment. The WHO has not set a formal health-based guideline value. It notes that a health-based value of 0.9 mg/litre could be derived, but that well-run treatment works achieve 0.1 mg/litre or less (large plants) and 0.2 mg/litre or less (small plants). The EU Drinking Water Directive lists aluminium as an indicator parameter at 200 µg/litre, and the US EPA has a secondary (non-enforceable) standard of 0.05–0.2 mg/litre.

A possible link between aluminium in drinking water and Alzheimer's disease has been investigated for decades. The WHO's assessment is that the relationship cannot be totally dismissed, but that there are strong reservations about inferring a causal link. What matters for a specifier is simpler: a fitting that adds aluminium to the water works against a parameter the water supplier is monitoring.

Brass, copper and stainless steel are in a different position: they have established acceptance routes — the European positive list of metallic compositions (Implementing Decision (EU) 2024/367, applying from 31 December 2026, and the national lists before it), NSF/ANSI/CAN 61 testing in North America, WRAS and the other Regulation 4 schemes in the UK, WaterMark in Australia. The European list names coppers, brasses, bronzes and stainless steels; there is no entry for aluminium alloys as a pipe or fitting material.

The Corrosion Argument

Separate from the water-quality question, aluminium has problematic corrosion behaviour in drinking water. Its resistance depends entirely on a thin oxide film, and that film is only stable between roughly pH 4 and pH 8.5–9:

Copper and other heavy-metal ions: This is the decisive problem in a building. Water that has passed through copper tube or brass fittings carries traces of dissolved copper; the copper plates out on aluminium surfaces downstream and sets up local galvanic cells that pit the aluminium (deposition corrosion). A plumbing system almost always contains copper or brass somewhere upstream.

Alkaline water (around pH 9 and above): The oxide film dissolves and the metal is attacked uniformly. Drinking water is allowed up to pH 9.5 in the EU, and lime softening or pH correction can take water to the top of that range — the edge of what aluminium tolerates.

Chlorides and direct contact with brass or copper: Chloride ions break down the oxide film locally and start pitting — the same mechanism as in marine environments. Screwed directly into brass or copper, aluminium is also the less noble partner of the galvanic couple and corrodes preferentially.

In summary: the range of water chemistry in which aluminium is stable is narrower than for copper, brass, or stainless steel. Potable water systems must work reliably across a wide range of water chemistries, and aluminium does not offer that reliability.

What You Should Specify Instead

Where Aluminium Is Legitimately Used Near Water Systems

There are applications near water systems where aluminium is entirely appropriate:

• Compressed air distribution in water treatment plants (not in contact with water)
• Structural brackets and frames supporting water system components
• Valve actuator bodies (pneumatic actuators on water valves) — the actuator is not in water contact
• Panel housings and enclosures for water treatment control equipment
• Irrigation fittings for non-potable agricultural water (with the limitations discussed in our irrigation guide)

The distinction is critical: aluminium is fine near water systems in non-contact roles. It is not acceptable in the water-contact roles that require potable water certification. Know which side of that line your application sits on, and specify accordingly.

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Frequently asked questions

Sources & references

Potable-water references:

Last reviewed: September 2026. Standards and regulatory references are checked at each review.