{"id":39625,"date":"2026-09-17T20:16:52","date_gmt":"2026-09-17T17:16:52","guid":{"rendered":"https:\/\/reoveemahutid.ee\/?p=39625"},"modified":"2026-09-17T20:21:20","modified_gmt":"2026-09-17T17:21:20","slug":"holding-tank-summer-house","status":"publish","type":"post","link":"https:\/\/reoveemahutid.ee\/en\/holding-tank-summer-house\/","title":{"rendered":"Sewage holding tanks for summer houses: planning for seasonal use"},"content":{"rendered":"

A summer house (suvila<\/em>) is busy for a few weeks and silent for months, and that rhythm decides how its wastewater is best handled. If you are sorting out summer house sewage in Estonia and your road has no mains sewerage, a sealed sewage holding tank (reoveemahuti<\/em>; in legal texts reovee kogumismahuti<\/em>; UK readers may know it as a cesspool or cesspit) copes well with such use: it stores wastewater until a tanker pumps it out (purgimine<\/em>), treats nothing and has no outlet. The short answer: size it by person-days and your longest stay, make sure a tanker can reach it, and do not leave it empty over winter where groundwater is high.<\/p>\n

Why a holding tank suits a house that stands empty<\/h2>\n

The Ministry of the Environment’s 2015 guide to on-site wastewater systems names private houses and summer houses as fits for a holding tank where, among other cases, water use is small or periodic. Its planning tables mark seasonal use as applicable to a holding tank and as “not possible” for biofilm and activated-sludge treatment plants. A holding tank has no treatment process, so nothing needs restarting in spring. The drawback is just as plain: every litre that goes in leaves by tanker, so the running cost is emptying.<\/p>\n

Whether a holding tank is required or one of several options depends on whether the plot lies in a sewage collection area (reoveekogumisala<\/em>; Water Act \u00a7 124) and on the municipality’s on-site wastewater rules (\u00a7 104(7)), which may add a setback (kuja<\/em>) or proof of emptying. Check the rules of the municipality where the summer house stands, not where you live. Installing the tank needs a building notice (ehitusteatis<\/em>) through the Building Register at least 10 days before work starts, then a use notice (kasutusteatis<\/em>).<\/p>\n

Occupancy-days arithmetic: count person-days, not months<\/h2>\n

A tank does not fill by the calendar; it fills by people being there.<\/p>\n

season volume (L) = person-days \u00d7 litres per person per day<\/code> tanker visits per season = season volume \u00f7 usable tank volume<\/code><\/p>\n

Worked example.<\/strong> A family of four uses the house on 16 weekends (32 days) and for a three-week holiday (21 days): 53 days, an occupancy share of about 0.15, or 4 \u00d7 53 = 212 person-days. At the ministry guide’s planning range of 100\u2013150 L of wastewater per person per day, that is 21.2\u201331.8 m\u00b3 a season. Living there permanently, the same family would produce 146\u2013219 m\u00b3 a year.<\/p>\n

The assumptions: 100\u2013150 L is a planning figure for permanent living; a summer house may use less, or more with a sauna and frequent guests. Sauna water piped to the same tank counts as inflow; a sauna building with its own drain is a separate calculation \u2014 see collecting sauna wastewater<\/a>. Your own water-meter data beats any planning figure; with an unmetered well, the first season’s emptying receipts show how many cubic metres were really taken away. Usable volume is taken as nominal volume; in practice the volume usable up to the alarm level is somewhat below nominal, so real intervals are somewhat shorter \u2014 check the drawing and alarm height for your model.<\/p>\n

Size for your longest stay, not the seasonal average<\/h2>\n

The seasonal total gives the budget: annual cost = visits per season \u00d7 your local price per visit<\/code> (ask whether the charge is per visit or per cubic metre). Tank size is decided by something else: how long the tank lasts while everyone is there.<\/p>\n

\n\n\n\n\n\n\n\n\n
Tank<\/th>\nFour people staying (400\u2013600 L\/day)<\/th>\nWeekends only (800\u20131200 L per weekend)<\/th>\nVisits in the example season<\/th>\n<\/tr>\n<\/thead>\n
3 m\u00b3<\/td>\n5\u20137.5 days<\/td>\nabout 2.5\u20133.75 weekends<\/td>\nabout 7\u201311<\/td>\n<\/tr>\n
4 m\u00b3<\/td>\nabout 6.7\u201310 days<\/td>\nabout 3.3\u20135 weekends<\/td>\nabout 5\u20138<\/td>\n<\/tr>\n
5 m\u00b3<\/td>\nabout 8\u201312.5 days<\/td>\nabout 4\u20136 weekends<\/td>\nabout 4\u20136.5<\/td>\n<\/tr>\n
6 m\u00b3<\/td>\n10\u201315 days<\/td>\n5\u20137.5 weekends<\/td>\nabout 3.5\u20135.5<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<\/figure>\n

Real visits round up, because nobody waits for the last litre. In the three-week holiday the example family produces 8.4\u201312.6 m\u00b3, so even a 5 m\u00b3 tank that starts the holiday empty needs one or two tanker visits during it and another soon after; six people fill it in about 5.5\u20138 days. The ministry guide advises ordering the tanker when the level passes about half the diameter \u2014 and ask how quickly the emptying company can come in July.<\/p>\n

Two limits apply. The guide notes that small tankers hold 4\u20135 m\u00b3 and the largest about 10 m\u00b3: a tank bigger than the tanker that can reach you cannot be emptied in one visit. And where \u00a7 47 of the Public Water Supply and Sewerage Act applies \u2014 collection areas of 2000 p.e. (population equivalents) or more without public sewerage \u2014 the tank must hold at least two weeks’ wastewater (\u00a7 47(7)); ask the municipality or water company how they assess that volume for a seasonally used house.<\/p>\n

Up to 5 m\u00b3, Vesmaco’s models come either long and shallow (for example MK-5 D1100, about 5.7 m long) or shorter with a deeper pit (MK-5 D1400, about 3.6 m); the 6 m\u00b3 models have a diameter of 1400 or 1600 mm: see the model table<\/a>.<\/p>\n

Narrow garden-cooperative roads: can the tanker reach you?<\/h2>\n

Many summer houses stand in garden cooperatives (aiandus\u00fchistu<\/em>) whose lanes were laid out for cars, not trucks. The ministry guide says tanker access must be guaranteed in every season. Before fixing the tank’s position, ask the emptying company that serves the area:<\/p>\n