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Sewage holding tank dimensions and drawings: choosing a model for your plot

Vesmaco’s model table lists 19 sewage holding tanks (reoveemahuti; in legal texts reovee kogumismahuti) from 2 to 15 m³, and most volumes come in two diameters. A holding tank only stores wastewater until a tanker pumps it out (purgimine): no treatment, no outlet. Once the volume is settled, the remaining choice is geometric — which shape suits your plot, your pipe depth and your digging conditions. Each model’s one-page drawing answers that and doubles as the order confirmation. Below: how to read the holding tank dimensions on that sheet, choose between a long, shallow tank and a short, deep one, complete the order fields, and pick the PDF or the DWG file.

One sheet per model: what the drawing contains

Each row of the model table has a PDF and a DWG button, in separate Estonian, English and Russian versions. The English sheets are titled “Cesspool”: UK readers may know a sealed tank of this kind as a cesspool or cesspit.

We checked six of the drawings: MK-2 D1100, MK-5 D1100, MK-5 D1400, MK-10 D1600, MK-15 D1600 and MK-15 D2000. All share one layout:

  • Title block (bottom right): model, drawing number, revision and issue date (all six: rev. B, 15.08.2025), sheet size A3 and scale (1:30 to 1:45).
  • Three views: a side view of the tank in the ground with the main dimensions; a top view with an arrow marking the inlet end; a 3D view showing the anchor straps.
  • Balloons 1–9, each matching the parts-list row with the same number.
  • Three boxes for h, the client’s approval and Vesmaco’s order approval.

A footnote reserves Vesmaco’s right to make changes, so download the drawing afresh when you order and check the revision letter.

The four numbers that matter

1. Length. The horizontal dimension under the side view, end to end of the tank body. On all six drawings it is 100 mm less than in the site’s model table (MK-5 D1400: 3500 mm against 3600 mm), so treat lengths as approximate — about 3.6 m for that model — and plan with the larger figure.

2. Diameter (Ø). 1100, 1400, 1600 or 2000 mm.

3. Inlet height above the tank bottom. The vertical dimension at the inlet end. On the six drawings we checked it is 1000 mm on D1100 tanks, 1300 mm on D1400, 1500 mm on D1600 and 1900 mm on D2000 — each time 100 mm below the tank top. Check the drawing for your model.

4. h, “installation height, max. 1500 mm”. The depth from the ground surface to the inlet, and the one number you supply; if you are unsure exactly which points it is measured between, ask the supplier. It is not a free choice: the Ministry of the Environment’s 2015 guide says installation depth follows the building’s sewer pipe, so your plumber or designer measures it. For installation deeper than 1.5 m, Vesmaco’s installation guide calls for a load-distribution reinforced-concrete slab above the tank.

Because the tank top sits about 100 mm above the inlet, soil cover over the tank is roughly h minus 100 mm; the ministry guide advises insulation where cover over pipe or tank is less than about 1.3 m.

A dashed blue line just below the tank top carries no label; ask the supplier what it marks. Usable volume is somewhat below the nominal volume — check the drawing and the alarm height for your model. Weight is not on the drawing; it is in the model table.

Long and shallow or short and deep: choosing a diameter family

Settle the volume first with What size sewage holding tank do you need?. Then compare shapes. Lengths (about) are from the site’s model table:

Volume Smaller diameter Larger diameter Length saved Extra depth
5 m³ D1100 · 5.7 m D1400 · 3.6 m 2.1 m 300 mm
6 m³ D1400 · 4.2 m D1600 · 3.3 m 0.9 m 200 mm
10 m³ D1400 · 6.7 m D1600 · 5.3 m 1.4 m 200 mm
15 m³ D1600 · 7.8 m D2000 · 5.2 m 2.6 m 400 mm

The 4 m³ pair follows the 5 m³ pattern and 7–9 m³ the 6 m³ pattern; 2 and 3 m³ exist only as D1100 (see 2–3 m³ sewage holding tanks), 12 m³ only as D1600.

“Extra depth” is arithmetic: pit depth = h + inlet height above tank bottom + bedding. Vesmaco’s installation guide requires at least 20 cm of compacted, stone-free sand under the tank; an anchored tank sits on a 20 cm reinforced-concrete slab with 20 cm of sand on top.

Family Inlet height Pit depth at h = 1000 mm Pit depth at h = 1500 mm
D1100 1000 mm 2.2 m 2.7 m
D1400 1300 mm 2.5 m 3.0 m
D1600 1500 mm 2.7 m 3.2 m
D2000 1900 mm 3.1 m 3.6 m

Assumptions: 200 mm sand bed, no anchoring slab (add at least 200 mm with one). This illustrates the difference between families; it is not a design. Pit and slab dimensions belong to your installer and a qualified designer.

  • The smaller diameter means a shallower pit, worth raising with your installer where groundwater is high or rock lies close to the surface. (The ministry guide calls anchoring essential in high groundwater, whatever the shape.)
  • The larger diameter helps where length is the limit — a narrow plot, trees, buildings, or delivery access for a tank up to about 7.8 m long. Allow for more than the tank: on a green area Vesmaco’s guide sets a safety zone 1 m larger than the tank in every direction.

For the most common volume decision, see 5 m³ or 10 m³ sewage holding tank.

Completing the order-confirmation fields

In the parts list, rows without the word “OPTION” are standard supply (tank, inlet pipe, maintenance shaft, plastic cap, D110 ventilation connection); rows marked “OPTION” are extras, with the quantity in brackets. Row 1 also states the material — GRP “Vesmaco Composite”, pH 3–10, heat resistance max. 60 °C — and the total volume.

  1. Row 2, inlet pipe: tick D110 or D160 to match the pipe from the house.
  2. Row 3, maintenance shaft (the emptying riser): PVC pipe D200, height 500–1000 mm, or as options pipe D400 (500–1000 mm) or shaft D600 (500–1500 mm). The riser bridges the gap from tank top to surface, roughly your h minus 100 mm, so a deep inlet may leave only the D600 range. Ask the supplier how riser height is measured and which riser suits your h.
  3. “Mark the location of the maintenance shaft”: four of the six drawings (MK-5 D1100, MK-10 D1600, both MK-15) offer three positions along the tank; MK-2 D1100 and MK-5 D1400 show one, so check the drawing for your model. Think of the tanker’s hose: the ministry guide says the tanker must not drive over the tank.
  4. Row 4, cover: plastic cap, or an EN 124 hatch in class A15, B125, C250 or D400 (1.5 to 40 t). Vesmaco’s guide says the class must suit the surroundings; describe the surface and ask. On vehicles the sources differ: the ministry guide says a holding tank must not go under a road or parking area, Vesmaco’s guide allows it with a load-distribution slab — a designer’s decision.
  5. Rows 6–9, options: ventilation pipe, plain or with an anti-odour filter; high-level alarm; anchor straps with tensioners. The manufacturer specifies the strap quantity per model: 2 on the MK-2 D1100 drawing, 4 on MK-5 D1400, 6 on the other four we checked — check the drawing for your model.
  6. The h box, date and signature. Vesmaco then completes product number, readiness date and approval.

Unsure about a field? Leave it blank and say so. Buying a sewage holding tank: 10 questions before requesting a quote explains how to find each answer.

PDF or DWG: which file for whom

PDF is for you, your installer and your municipality. Print it, tick, sign, scan. The sheet is drawn to scale on A3; printed on A4 the scale no longer holds, so read the written dimensions, not a ruler.

DWG is the CAD format used by AutoCAD and compatible software. Send it to your designer or architect, who can use it to place the tank on the site plan, check distances to boundaries, wells and buildings, and draw the sewer run to the inlet. If they need a particular file version or scale, they can ask the supplier.

Frequently asked questions

Is the manufacturer’s drawing enough for the building notice? For installing a holding tank, the Building Code (Annex 1) lists a building notice (ehitusteatis), filed through the Building Register (ehitisregister, ehr.ee) at least 10 days before work starts, and no building permit or design documentation. A use notice (kasutusteatis) follows at least 10 days before use. The authority may add requirements (§ 36(5)), so ask your municipality what to attach. Saaremaa, for example, asks for conformity certificates at commissioning, so ask the supplier which conformity documents come with the tank.

Does the drawing tell me how much room the tank needs on the plot? Only the tank itself; the pit, the safety zone and the setback (kuja) come on top. The national setback regulation does not mention holding tanks; according to Keskkonnaamet’s handbook a municipality may set one in its on-site wastewater rules. Kuja is measured from the structure’s outer contour, so length and diameter count. Saaremaa, as an example only, uses 5 m. Check your own municipality.

Can I order a different length or inlet position? The drawings we checked show fixed dimensions and a single inlet at one end. If no standard model fits, describe the constraint in your enquiry and ask whether a non-standard length, inlet position or extra connection is possible.

Download the drawing, mark your options, attach it to the enquiry form. Open the model table, download your model’s PDF, tick the fields you are sure of and write in h. Attach it to the enquiry form, which accepts files, with a line about your plot. Vesmaco manufactures the tanks, advises on the choice and delivers across Estonia; installation stays with your installer. The site says replies usually come within 2–3 days; for urgent questions call +372 641 8550.

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