A drinking water storage tank must keep water away from light, dirt and anything the tank material could release, and it must be easy to drain and clean. For sectional tanks that means GRP or AISI 304 / 316 L stainless steel panels; we do not recommend galvanized steel for drinking water. A sealed, opaque roof, a fully drainable floor and regular maintenance matter as much as the material.
Contents
- What makes a tank suitable for potable water?
- Five features of a hygienic drinking water tank
- GRP panels: opaque, with no heavy metals or phenol detected
- Stainless steel potable water tanks: AISI 304 / 316 L
- Drainage, cleaning and maintenance
- Insulation and condensation
- Why we do not recommend galvanized steel for drinking water
- Where sectional potable water tanks are used
- Frequently Asked Questions
What makes a tank suitable for potable water?
A potable water tank is a closed tank that stores drinking and domestic water without changing its quality. Whether you call it a drinking water storage tank, a potable water tank or a sectional potable water tank, it needs a material that is safe in contact with drinking water, a sealed roof, and a floor that drains fully so the tank can be entered and cleaned.
National rules set the baseline. In Turkey, for example, Article 13 of the Regulation on Water Intended for Human Consumption (Official Gazette of 17 February 2005, No. 25730) requires surfaces in contact with drinking water to be made of materials that do not impair water quality or harm health. Check which approvals apply in your country before you specify a tank.
Five features of a hygienic drinking water tank
A hygienic potable water tank combines five features:
| Feature | Why it matters | In Aquatank tanks (catalogue) |
|---|---|---|
| Opaque panels | Light lets algae grow. | GRP panels are opaque; no algae forms inside (pp. 5, 8) |
| No leaching | The tank must not change the taste or chemistry of the water. | Heavy metals and phenol "not detected" for the GRP panel (p. 8) |
| Fully drainable floor | Leftover sediment undermines cleaning. | GRP tanks: convex floor and a drain panel at the lowest point (pp. 9, 11) |
| Cleanable surface | Smooth surfaces are easier to wash. | GRP panels are smooth on both faces (p. 5) |
| Closed roof, manhole and vent | Dust, insects and rain must stay out. | GRP tanks: opaque closed roof with a manhole cover and air vent (p. 10) |
GRP panels: opaque, with no heavy metals or phenol detected
Aquasan GRP panels are UV resistant and opaque, so no algae forms inside the tank, and the roof is closed with opaque, cross-ribbed panels (catalogue pp. 5, 10, 11). The catalogue's physical properties table gives these values for the GRP panel (p. 8):
- Light transmission: none
- Heavy metals: not detected
- Phenol: not detected
- pH (20 °C): 6.9
- Water absorption rate: 0.01%
The catalogue states that the food-contact suitability of the GRP panels is documented by laboratory reports (pp. 6, 21). For our documents, see the Certificates page. More on the material in What is a GRP water tank?
Stainless steel potable water tanks: AISI 304 / 316 L
Stainless steel sectional tanks are built from 1,080 × 1,080 mm pressed panels in AISI 304 or 316 L. Our catalogue lists "highest hygiene, corrosion resistance" as their key feature and states that no algae or bacteria form in stainless steel tanks (catalogue pp. 4, 14). Standard capacities run from 1.26 to 90 m³, with heights of 540–4,320 mm in 540 mm steps; intermediate sizes and custom capacities are made to suit the project (pp. 15, 16). Grade 316 L contains molybdenum and resists chlorides better than 304. See stainless steel water tanks.
Drainage, cleaning and maintenance
A potable water tank must drain completely, or sediment stays behind after every clean. Our catalogue states that the floor design of Aquasan tanks allows dirty water and sediment to be drained completely (catalogue p. 9). In GRP tanks this is done with:
- Convex floor panels direct water to the drain point, and water pressure compresses the joints for a tighter seal (pp. 9, 11).
- A drain panel at the lowest point of the floor empties the tank fully (p. 11).
- A roof manhole and internal ladder give access for cleaning (p. 10).
Our periodic maintenance covers cleaning, disinfection and inspection, with panels, gaskets and fasteners in stock (p. 18). See our service network.
Insulation and condensation
For very hot or very cold regions, GRP panels can be insulated with 25 mm of CFC- and HCFC-free polyurethane foam behind a protective cover. According to the catalogue, this three-layer panel prevents condensation on the outside and minimizes temperature change in the stored water (catalogue pp. 5, 12). Thermal conductivity falls from 0.15 kcal/m·h·°C for plain GRP to 0.02 for insulated GRP, against 37.0 for steel (p. 12).
Why we do not recommend galvanized steel for drinking water
In the TSEK certificate shown in our catalogue, the galvanized modular tank is classified as "not intended for drinking or domestic-use water", while the stainless steel tank is listed for drinking and domestic-use water (catalogue p. 21). Galvanized tanks are strong and economical (p. 4) and suit fire, process and irrigation water. See galvanized steel water tanks.
For document names, scope and validity dates, see our Certificates page. If your specification calls for a particular approval, tell us when you request a quote.
Where sectional potable water tanks are used
Sectional drinking water tanks serve housing, hospitals, schools and dormitories, and public buildings (catalogue p. 4). References listed in the catalogue (pp. 19, 20) include Dr. Dakheel Hospital in Erbil, Ardahan State Hospital, Uludağ University in Bursa and housing projects across Turkey for TOKI (Turkey's Housing Development Administration); see Projects.
Partitioned tanks: one tank can hold drinking water and fire water in two compartments. Because separate tanks need a 1 m maintenance gap between them, a 2 × 4 × 2 m partitioned tank holds 16 m³ on the same footprint where two separate 2 × 1.5 × 2 m tanks hold 12 m³ (p. 13). To size your tank, see water tank sizing.
Frequently Asked Questions
Can drinking water be stored in a galvanized tank?
We do not recommend it. The TSEK certificate shown in our catalogue classifies the galvanized modular tank as "not intended for drinking or domestic-use water" (catalogue p. 21). Use galvanized tanks for fire and process water.
Can one tank hold drinking water and fire water?
Yes. A partition panel divides the tank into two compartments, and both faces of the panel are made for contact with water (catalogue pp. 11, 13).
Can a potable water tank be installed outdoors or on a roof?
A GRP tank can. The panels are UV resistant and opaque and are used outdoors in very hot and very cold climates, with insulated panels available (catalogue pp. 6, 12). On a roof, have the structure checked for the weight of the full tank (1 m³ of water weighs about 1 tonne). Tell us whether the tank goes indoors, on a roof or outdoors when you request a quote (p. 23).
How often should a drinking water tank be cleaned?
In Turkey, the Ministry of Health's General Directorate of Public Health recommends cleaning water tanks inside buildings at least once a year. We also recommend having the tank inspected and cleaned without waiting for that interval if the colour, odour or taste of the water changes, or after an earthquake, a flood or a long period out of use. Check the requirements that apply in your country. Our periodic maintenance service covers cleaning, disinfection and inspection (catalogue p. 18).
Get a quote for your project
Share the required capacity (m³), application and location; our engineers will reply with a recommended panel type, size and material.