Water Tank and Borewell Vastu

Few Vastu questions are asked as often, or as late, as the one about water tanks. A family has bought a plot, the plan is nearly final, and someone asks where the borewell should be drilled and where the overhead tank will sit. Or the house is already built, and a relative mentions that the sump is in the wrong corner. Because water storage involves digging, heavy structure and plumbing, a decision made casually at the start is expensive to change later — which is exactly why it deserves a calm, informed look before construction begins.

Vastu tradition has clear preferences for water: underground water towards the north-east, heavy stored water high up towards the south-west. Building practice has its own non-negotiables: drinking water must be kept far from sewage, a full overhead tank is a load of a tonne or more that the structure must carry, and pipes must reach every tap with enough pressure. In most well-planned houses these two sets of rules agree more often than people expect. Where they conflict, safety and hygiene must win, and the tradition itself offers ways to adapt.

This article explains the traditional directions for sumps, borewells, wells and overhead tanks, the reasoning usually given for them, and the practical engineering that sits beside them. It includes dimensioned drawings, sizing tables, indicative October 2026 costs, and honest guidance for flats and small plots where the ideal position is simply not available. As with the other Vastu articles on this site, the tradition is presented as tradition — a body of guidance many families value — not as a building code.

Where the tradition comes from

Vastu shastra is the traditional Indian body of knowledge on building, recorded in architectural treatises such as the Mayamata and the Manasara and transmitted through generations of sthapatis and practitioners. It divides a site into directional zones on a square grid, the vastu purusha mandala, and associates each zone with an element and a character. The north-east (Ishanya) is associated with water, sacredness and light; the south-east (Agneya) with fire; the south-west (Nairutya) with earth, weight and stability; the north-west (Vayavya) with air and movement; and the centre (the Brahmasthan) is kept open and unburdened.

Water placement follows directly from this map. Water that lies low — a well, a stepwell, a tank in the ground, today a sump or a borewell — belongs to the water zone in the north-east, or more broadly the north and east. Water that is stored high and heavy — a rooftop tank — belongs where weight is welcome, in the south-west, or failing that the west or south. Water and fire are kept apart, so neither underground nor overhead water is placed in the south-east. And the centre, which the tradition keeps free of weight and pits, holds neither. Wells and water tanks have of course existed in Indian homes for centuries; the modern borewell and the plastic overhead tank are simply new forms that inherited the old rules.

Practitioners differ on details, especially for septic tanks and secondary tanks, and the table records the most common positions rather than a single authoritative rule. Families who follow a particular practitioner or regional tradition should treat their advice as the reference; what the table shows is the broad pattern that most traditions share.

The Vastu grid with water marked on it

Tradition and engineering: where they agree

Read as design guidance, several of these preferences line up well with practical logic — though the practical reasons are modern explanations, not claims about what the original authors intended. The most important agreement is separation. A tradition that puts drinking water in one corner and waste in a different, distant zone produces, on most plots, exactly what public health engineering asks for: a large distance between the water source and the septic tank or soak pit, so that sewage cannot seep into the groundwater being drawn up.

A second agreement concerns access and daylight. On plots facing north or east — the facings many families prefer — a sump in the north-east is near the gate, which makes filling it from a municipal connection or a water tanker simple, and keeps the manhole in an open, bright, easily cleaned corner of the front yard. A third concerns structure: the tradition's wish to keep the centre of the house free of weight and pits is good sense, because the centre of a house is where a sump excavation could undermine the most foundations, and where a rooftop load is least easily carried to the ground.

Separation: the rule that comes before every direction

Whatever the directions, a borewell, well or underground sump that holds drinking water must be kept well away from a septic tank, soak pit or any sewage line. Indian guidance on septic tanks and sub-surface absorption systems (IS 2470) and public health practice give separation distances, which depend on soil type, groundwater level and the type of water source. A separation of 15 m or more between a borewell or well and a septic tank or soak pit is a commonly used aim, and more is needed in sandy or fissured ground and where the water table is high. The sump itself must be watertight, with a raised, sealed manhole cover, so that surface water and sewage cannot enter it.

On large plots and farmhouses this is easy. On urban plots it often is not. A 30 × 50 ft plot has a diagonal of under 18 m; once the borewell and the septic tank are kept a little away from the boundary walls, the realistic maximum separation may be 12–14 m. In that situation, the correct answer is not to squeeze them into the furthest corners and hope. It is to connect to the municipal sewer if one exists and drop the septic tank altogether, or to use a properly designed, sealed treatment system with no soak pit, or to rely on municipal water and a sealed sump and drill no borewell. A qualified plumbing or public health engineer should make that call.

The overhead tank: weight, height and heat

Water weighs one kilogram per litre, so a full 1,000-litre overhead tank is a load of a little over a tonne, and a 2,000-litre tank over two tonnes, before the weight of the tank and its stand. That load must reach the ground through walls or columns designed for it. In most houses the natural place is above the staircase headroom structure (the mumty) or over the toilet block, where walls run all the way down. This is often in the west or south-west of the plan, which is why the traditional preference and the structural preference frequently coincide. What should never happen is a large tank placed in the middle of a roof slab, or on a slab edge, because a relative mentioned the south-west corner. The structural engineer, not the compass, decides where the load can go; the compass then chooses between the safe options.

Height decides pressure. Every metre of height between the water level in the tank and a tap gives about 0.1 bar of pressure (10 m of head is roughly 1 bar). A tank on a 1500 mm stand on the terrace of a G+1 house gives the ground floor good pressure, but a first-floor shower directly below the roof may get only about 0.2–0.3 bar, which feels weak with modern fittings. The solutions are a taller stand where the structure and bye-laws allow, a small pressure pump on the top floor's supply, or both. The south-west location brings one more practical issue: it is the most sun-exposed corner of the roof in Indian summers, so a black plastic tank there will deliver hot water to cold taps in May. A light-coloured, insulated or shaded tank solves it.

Fig. 3 shows the usual arrangement in a G+1 house: an underground sump filled from the municipal line or a tanker, a pump that lifts water to the overhead tank, and gravity supply from the tank to every tap. A level controller that starts the pump when the tank is low and stops it when it is full, and protects the pump from running dry when the sump is empty, is inexpensive and prevents both overflowing tanks and burnt-out pumps. The overflow pipe from the tank should discharge where it is visible, so a failed controller is noticed, and every tank and sump needs a tight lid to keep out light, dust, insects and birds.

Sizing the sump and overhead tank

Storage is sized from daily demand, supply pattern and family size. Indian planning guidance — IS 1172 and the National Building Code of India 2016, Part 9 (Plumbing Services) — gives per-person domestic demand ranges that depend on city size and on whether the home has full flushing; about 135 litres per person per day is a commonly used figure for homes with full flushing, with larger cities planning for more. A common practice is to keep overhead storage for roughly half a day to a full day of use, and sump storage for one to two days, more where the municipal supply comes only on alternate days. The table applies that practice; a plumbing engineer adjusts it for the actual supply pattern.

Borewells: law, geology and recharge

A borewell is not just a Vastu question; it draws on a shared groundwater resource. The Central Ground Water Authority and state groundwater departments regulate groundwater extraction, and in notified or over-exploited areas drilling may need prior permission or registration, even for domestic use. Many municipal corporations also require registration of borewells and may require rainwater harvesting with any new building. Before drilling, check the local rules, ask neighbours about depth and water quality in the area, and use an experienced drilling contractor. Depth and yield vary enormously with local geology, which is why costs are so wide.

Position the borewell clear of the house's foundations — drilling vibration and the hole itself should not be close to footings — with access for the drilling rig, which needs a clear approach from the gate. On most plots that means the front setback, which on north- and east-facing plots is the north-east or north and fits the traditional preference. Test the water before using it for drinking; in many parts of India borewell water carries dissolved salts or other contaminants that need treatment.

Rainwater recharge is the responsible partner of a borewell. Roof water is led through a filter or silt chamber into a recharge pit — commonly 1200–2000 mm across and 2000–3000 mm deep, filled with layers of boulders, gravel and coarse sand — from which it soaks down to the aquifer. Only clean roof water should be recharged; water from roads, paved areas or drains carries oil and contamination. In Vastu terms the recharge pit is underground water and fits the same north, east and north-east zones as the borewell; in practical terms it should be near the borewell's catchment, away from foundations, and away from the septic tank by the same margin as the borewell.

Indicative costs, October 2026

The figures below are indicative October 2026 ranges for a typical house in Gujarat and similar regions. Borewell costs in particular vary with depth, geology and casing, and every item should be quoted locally. Where this site's farmhouse and home-automation articles quote a related item, the same range is used here.

Flats, existing homes and small plots

In apartments, the family usually controls none of the water system: the sump, the borewell and the overhead tanks are part of the building, placed by the builder's architect and engineer for structural and services reasons, and often shared. Vastu books written for independent houses do not translate directly. What residents can influence is inside the flat — where a water purifier, a storage drum or a small loft tank sits — and here the tradition's general preferences (water storage towards the north or east of the flat, not in the south-east kitchen corner if avoidable) can be followed without any building work.

Whatever the situation, demolishing a sound sump or relocating a borewell purely on directional grounds is rarely a good use of money. Many practitioners themselves advise remedial measures rather than demolition for built homes, and the design answer — keeping the existing system clean, sealed, well-lit and well-maintained — is consistent with what the tradition values. For new construction, the cheapest moment to satisfy both tradition and engineering is before the foundation drawings are issued.

Where water planning is heading

Water storage at home is changing faster than most other services. Falling groundwater tables in many Indian cities are making rainwater harvesting and recharge a requirement rather than an option. Smart level sensors and app-based pump controllers are replacing float switches, and some municipalities are moving towards metered 24-hour supply, which may shrink the need for large sumps in future. Greywater reuse for flushing and gardens is spreading in larger homes and apartment complexes, adding a second, separate tank that must never be cross-connected with drinking water. Each of these adds pipes, tanks and pits to the plan — and each can be placed with the same two filters used in this article: engineering and hygiene first, traditional preference second.

Rules for placing water tanks and borewells

• Keep any borewell, well or drinking-water sump far from septic tanks and soak pits — 15 m or more is a common aim; if the plot cannot give it, connect to a sewer, use a sealed system or skip the borewell.
• Prefer the north-east, north or east for underground water and the recharge pit, and keep the centre and south-east free of water storage.
• Prefer the south-west, west or south for the overhead tank — but only where walls or columns designed for the load carry it, usually the stair or toilet core.
• Size storage at about 135 litres per person per day: overhead for half to one day, sump for one to two days, more with alternate-day supply.
• Remember the load (1 litre = 1 kg) and the pressure (10 m head ≈ 1 bar); add a pressure pump for top-floor showers.
• Use light-coloured or insulated tanks on sun-exposed roofs, and tight lids on every tank and sump.
• Fit a level controller with dry-run protection, and let the overflow discharge where it can be seen.
• Check groundwater rules, test borewell water before drinking, and recharge only clean, filtered roof water.

Frequently asked questions

Which direction is best for an underground water tank as per Vastu?

Traditional Vastu prefers the north-east, with north and east also commonly accepted. The south-west, south-east and centre are traditionally avoided. Practically, the sump must be watertight, sealed and well away from any septic tank or sewer line.

Where should the overhead water tank be placed as per Vastu?

The south-west is traditionally preferred, with west and south accepted; the north-east and centre are avoided. The tank must sit where the structure is designed to carry it — usually over the staircase or toilet core — and a structural engineer should confirm the position.

Can a borewell be in the south-west?

Traditional Vastu avoids it, preferring the north-east, north or east. If the only safe or legal position for a borewell is elsewhere — for example to keep it far from a septic tank — hygiene and safety should take priority, and many practitioners suggest remedies rather than an unsafe position.

What is the minimum distance between a borewell and a septic tank?

A separation of 15 m or more is a commonly used aim, with more in sandy or fissured soils and where groundwater is shallow. IS 2470 and local health guidance apply. If a plot cannot provide a safe distance, connect to the municipal sewer, use a sealed treatment system, or avoid drilling a borewell.

What size water tank does a family of four need?

At about 135 litres per person per day, a family of four uses roughly 550 litres a day. A 1,000-litre overhead tank and a 1,500–2,500 litre sump are typical choices, with a larger sump where supply is not daily.