Stainless Steel vs. Copper in Drinking Water: Which is Better?
Anyone planning a drinking water installation faces a choice: stainless steel or copper? Both materials are DVGW-certified and have been in use for decades — but they differ significantly in terms of hygiene, corrosion behavior, and cost. Which option is right depends less on the installer's preference than on the local water quality and the requirements of the property.
The decision warrants careful consideration, as a drinking water installation is laid for decades and can only be corrected later with great effort. This direct comparison contrasts both materials with their strengths and weaknesses, explains the rules of mixed installation, and uses a cost example to show which material is the better choice for your installation.
Stainless Steel Press Fittings (Sanha NiroSan): Advantages and Disadvantages
Stainless steel is considered the premium material in drinking water installations — and for good reason. The surface is largely chemically inert: practically no metal ions are released into the water, the taste remains completely neutral, and its resistance is independent of water hardness and pH value. Where water quality fluctuates or is unknown, you are on the safe side with stainless steel.
Added to this is the smooth inner surface of the pipes, which makes deposits and biofilm formation more difficult — a real hygiene advantage over the entire service life. However, this quality comes at a price: the material costs significantly more than copper, and processing requires suitable tools with the correct pressing contours. For the pressing itself, once you master the system, you can work as quickly as with copper.
Advantages of Stainless Steel
- Highest hygiene — no heavy metal dissolution
- Corrosion resistant with any water
- No taste — neutral
- UBA Drinking Water List without restriction
- Smooth inner surface — no bacteria
- Service life 80+ years
- 100% recyclable
Disadvantages of Stainless Steel
- Material 2–3 times more expensive than copper
- More difficult to work with when welding
- Special tools required (V-contour press jaws)
Copper Press Fittings (SANHA-Press): Advantages and Disadvantages
Copper is the proven classic of domestic installations and has proven reliable over generations of installers. The material is excellent to process, widely available in trade, and the antibacterial effect of copper ions is a real plus: it inhibits the growth of germs like legionella in the piping network.
The weak point of copper lies in its dependence on water chemistry. In soft, acidic water, copper can dissolve from the pipe wall — this contaminates the drinking water and can lead to pitting corrosion in the long term. Whether copper is suitable for your region can be determined by consulting your utility's water analysis, which indicates hardness and pH value. The fluctuating price of copper also makes the calculation of larger projects more difficult than with price-stable stainless steel.
Advantages of Copper
- Proven standard for 60+ years
- Antibacterial effect — copper ions act against legionella
- Cheaper than stainless steel
- Easy to process
- Recyclable
Disadvantages of Copper
- With soft water: copper dissolution possible
- With pH value < 7: corrosion
- Discoloration of sanitary fixtures
- Volatile material price (copper price fluctuates)
You can read more about connection technology in the comparison Press vs. Soldered Fittings.
When Stainless Steel, When Copper?
The choice of material can be boiled down to a simple basic rule: the softer and more acidic the water, the more clearly everything speaks for stainless steel — the harder and more alkaline, the less problematic copper is. In between, the type of property and requirements decide: In sensitive buildings such as clinics, nursing homes, or hotels, the hygienic safety of stainless steel is the more important argument; in standard residential construction, the cost advantage of copper may be decisive.
Existing installations also play a role: anyone extending or renovating an existing copper installation should sensibly stick to the proven material — provided the water values allow it. For new builds with unclear or fluctuating water quality, stainless steel is the less risky choice because it copes with any water.
Stainless Steel is recommended for
- Soft water (< 8°dH)
- Low pH value (< 7.5)
- Premium properties (nursing home, clinic, hotel)
- Safety-relevant drinking water installations
- Mixed installation (compatible with everything)
Copper is recommended for
- Hard water (> 14°dH) and high pH value
- Standard residential construction (cost optimization)
- Renovation with existing copper system
- Heating installation (proven)
Mixed Installation: What is allowed?
In practice, different metals meet more often than one might think — for example, during partial renovations or extensions. The so-called flow rule applies: the nobler metal belongs downstream of the less noble one, otherwise dissolved ions of the nobler metal can cause corrosion on the less noble one. The following table shows which combinations are permissible.
| Before | After | Allowed? |
|---|---|---|
| Stainless Steel | Stainless Steel | Yes |
| Stainless Steel | Copper | Yes (in flow direction) |
| Copper | Stainless Steel | Caution (corrosion possible) |
| Copper | Galvanized Steel | No (galvanic corrosion!) |
| Stainless Steel | Galvanized Steel | No |
Pro Tip: Always use stainless steel at the end of the flow direction. When renovating galvanized systems, replace the entire installation! Our guide on drinking water hygiene explains how to avoid stagnation and legionella.
Cost Example Single-Family House and Sanha Product Range
A typical single-family house scenario shows the practical price difference. It's noteworthy that the working time is identical for both systems, as the pressing technique works equally fast for stainless steel and copper. The difference therefore lies solely in the material — and is relativized when spread over the lifespan of the installation.
Calculation example: 80 m piping + 30 fittings.
| Stainless Steel (NiroSan) | Copper (SANHA-Press) | |
|---|---|---|
| Total Material | ~ €1,500 | ~ €700 |
| Working Time | ~ 6 h | ~ 6 h |
| Total Material Cost | €1,500 | €700 |
Stainless steel material is roughly twice as expensive. However, with a lifespan of 80+ years and health safety, it is usually the right choice — calculated over the period of use, the surcharge is only a few euros per year.
The Sanha Complete Range
The manufacturer Sanha covers practically every application in building services with its system lines — from premium drinking water and heating to aggressive media. The advantage of a consistent system: press jaws, contours, and processing rules remain uniform, which reduces sources of error on the construction site.
- Sanha NiroSan — Stainless steel 1.4404, premium drinking water
- SANHA-Press — Copper, standard drinking water
- Sanha NiroTherm — Carbon steel, heating
- Sanha 3fit-Press — Silicon bronze, aggressive media
- SANHA-Heat — Heating circuit components
- SANHA Ball Valves — Shut-off valves
Press fittings and pipes for heating and drinking water can be found in the categories Heating Pipes & Press Fittings and Pipe Systems.
Frequently Asked Questions
Is stainless steel or copper more hygienic?
Both are DVGW-certified. Stainless steel is more neutral, copper has an antibacterial effect. For soft or acidic water, prefer stainless steel — copper can dissolve in such water.
Can I mix copper and stainless steel?
Yes, but install stainless steel downstream of copper — otherwise there is a risk of corrosion. If in doubt, refer to the flow rule table above.
How long does copper last?
50–70 years with normal water. Shorter with soft or acidic water — in which case stainless steel, with 80+ years, is the more durable choice.
Conclusion
Stainless steel excels with maximum hygiene and lifespan, while copper offers lower costs and proven technology — water hardness and local pH value are decisive. Before choosing materials, check your utility's water analysis and consider the property type: in sensitive buildings, stainless steel is almost indispensable, while in standard residential construction with hard water, copper remains a solid and economical solution. And if you mix, consistently adhere to the flow rule. Everything for your drinking water installation can be found in the Sanitary assortment of wohnungstechnik.de.
