A water tank should be selected by usable volume, water source, water quality target, installation structure, and cleaning access, not by capacity alone. For homes, commercial buildings, RO skids, and refill-water businesses, the right tank stores the required operating volume plus reserve, uses a material compatible with the water, blocks light, includes a covered vent and drain, and sits on a base that can carry the full filled weight. If the water is for drinking or food contact, the tank is only one part of the system; filtration, disinfection, and laboratory testing still determine whether the water is acceptable.
PT Watermart Perkasa supplies water storage and ancillary tanks, FRP pressure tanks, Codeline RO pressure vessels, automatic control valves, cartridge filters, and dosing pumps for water-treatment systems in Indonesia.
Tips for Choosing a Water Tank
Start from the water balance. List the source flow, peak demand, treatment flow, backwash demand, and minimum reserve. A tank that is too small causes pump cycling and service interruptions; a tank that is too large can create long residence time, sediment buildup, and avoidable cleaning work.
| Decision point | Practical rule | Why it matters | Product handoff |
|---|---|---|---|
| Usable capacity | Required volume = daily demand x autonomy days + reserve. Keep dead volume and outlet height in mind. | Nominal tank size is not always the same as usable water above the outlet. | Water tank products |
| Filled weight | 1,000 L of water weighs about 1,000 kg before tank, frame, pipe, and live loads. | Roof slabs and steel towers must be checked for the filled condition, not the empty tank. | FRP and pressure tanks |
| Source quality | Well water with iron, manganese, hardness, or odor needs pretreatment before the clean-water tank. | A tank does not remove contaminants; it can only store the water it receives. | GreensandPlus iron and manganese pretreatment and DIONIX resin |
| Treatment process | RO systems usually need a raw-water buffer, cartridge prefilter, RO membrane train, and clean-water tank. | Separating raw and treated storage prevents untreated water from mixing with product water. | Reverse Osmosis systems and Codeline vessels |
| Access and hygiene | Specify a manhole, drain, screened vent, overflow, level control, and isolation valves. | Tanks that cannot be isolated, drained, or inspected are hard to maintain safely. | Control valves and dosing pumps |
Use the table below as a sizing method, not a universal standard. Replace the demand number with measured consumption, meter data, or the treatment plant design flow.
| Example demand | Reserve assumption | Calculated storage | Typical procurement note |
|---|---|---|---|
| 800 L/day small utility demand | 1 day + 20 percent reserve | 960 L | Choose a 1,000 L class tank or split into 2 x 500 L when access is tight. |
| 3,000 L/day building demand | 1 day + 20 percent reserve | 3,600 L | Use one 4,000 L class tank or parallel tanks so one unit can be isolated for cleaning. |
| 10,000 L/day refill-water or process demand | 0.5 day + 20 percent reserve | 6,000 L | Size raw and treated tanks separately; match them to RO or filtration production rate. |
For rooftop placement, ask a qualified civil or structural engineer to check the slab, tower, anchor, wind exposure, and seismic restraint. For ground-level placement, plan pump suction, drainage, flood protection, and safe access for cleaning crews.
Assortment of Tank Panels
Water tanks are commonly grouped by material and pressure duty. The most important distinction is whether the tank is atmospheric storage, such as a rooftop or ground tank, or a pressure vessel used inside a filtration, softener, or RO system.
| Tank type | Best fit | Main strength | Watch-outs |
|---|---|---|---|
| Polyethylene atmospheric tank | Clean-water storage for homes, buildings, small treatment plants, and refill-water businesses. | Light, corrosion resistant, widely available in many sizes. | Confirm potable-water suitability, UV protection, opaque wall, manhole, drain, and overflow details. |
| Stainless steel tank | Indoor or protected installations where appearance, cleanability, and rigidity matter. | Rigid and easy to wash when fabricated correctly. | Chloride-rich water, coastal air, poor welding, or incompatible chemicals can cause corrosion. |
| Fiberglass or FRP atmospheric tank | Larger custom storage, chemical service, or industrial sites. | Good corrosion resistance when resin and laminate are specified for the water. | Quality depends on laminate design, internal coating, UV protection, and manufacturer control. |
| FRP pressure tank | Media filters, softeners, demineralizers, and pretreatment vessels. | Designed for pressurized water-treatment processes. | Not a substitute for open storage; select by pressure rating, diameter, valve, distributor, and media bed. |
Fiber Glass Toren Tank
Fiberglass or FRP tanks can work well when the resin, laminate thickness, coating, and fittings match the water chemistry and installation environment. They are often selected for industrial storage or as pressure tanks in filtration and softening systems.
Check the specification carefully. For atmospheric storage, ask for UV protection, a clean internal surface, a secure manhole, overflow, drain, and vent screen. For pressurized filtration service, use a purpose-built FRP pressure tank and match it with the right distributor, media bed, and control valve.
Stainless Steel Water Tank
Stainless steel tanks are useful where the buyer needs a rigid, washable tank and can control the water chemistry. They are common in protected indoor or utility-room installations and in projects where visual finish matters.
Do not assume every stainless tank is suitable for every water source. Chloride, low pH, poor weld finishing, stagnant crevices, and coastal exposure can shorten service life. If the source is well water, brackish water, or chemically dosed water, check chloride, pH, iron, manganese, and cleaning chemicals before specifying stainless steel. The tank also still needs a dark interior, covered vent, drain, overflow, and inspection access.
Polyethylene Water Tank
Polyethylene tanks are the default choice for many clean-water storage duties because they are light, corrosion resistant, and easy to move before installation. For outdoor service, choose an opaque tank with UV-stabilized material so sunlight does not encourage algae growth inside the stored water.
For potable or food-contact use, ask for documentation that the tank material is suitable for drinking-water storage. Also check wall thickness, lid fit, outlet reinforcement, float-valve access, overflow size, and whether the tank can be drained completely during cleaning.
Potable-water and regulation notes
Tank selection cannot make unsafe water safe. If the tank serves drinking water, refill-water production, food and beverage operations, hotels, hospitals, or employee facilities, test both source water and stored water. In Indonesia, check the latest applicable requirements under Minister of Health Regulation No. 2 of 2023, including the parameter set for the intended use.
For hygiene and sanitation water, the regulation includes limits such as E. coli 0 CFU/100 ml, Total Coliform 0 CFU/100 ml, TDS below 300 mg/L, turbidity below 3 NTU, pH 6.5-8.5, dissolved iron 0.2 mg/L, and dissolved manganese 0.1 mg/L. Drinking-water projects may require a different or broader parameter list, so confirm the sampling plan with a qualified laboratory.
If your next step is water-quality verification, A3 Laboratories at lab.id provides water testing and water-quality analysis for clean water, drinking water, RO water, wastewater, groundwater, and seawater.
Maintenance checklist
| Frequency or trigger | What to check | Action |
|---|---|---|
| Monthly visual check | Lid, vent screen, overflow, insects, odor, color, sediment, leakage, and pump cycling. | Tighten covers, clear the overflow, record abnormal odor or color, and schedule cleaning if sediment is visible. |
| After construction, flooding, open-hatch work, or contamination complaint | Dirt entry, broken cover, dead insects, unusual smell, or changed water quality. | Isolate the tank, clean and disinfect as appropriate, flush the line, and retest before potable use. |
| Scheduled cleaning interval | Sediment depth, biofilm, internal surface condition, float valve, level sensor, and drain function. | Drain safely, clean internal surfaces, inspect fittings, restore covers, and document the service date. |
| Treatment-system service | Cartridge pressure drop, media backwash, RO permeate quality, dosing pump operation, and tank turnover. | Replace cartridges, adjust controls, check dosing pump output, and keep raw-water and treated-water tanks separated. |
When to ask Watermart
Ask Watermart when the tank is part of a treatment train, not just a standalone container. The selection should be coordinated with pumps, filters, valves, RO membranes, pressure vessels, chemical dosing, and the intended water-quality target. For procurement support, send your source-water data, daily demand, peak flow, installation location, and available floor or roof space through the Watermart contact page.