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Seven weeks of summer.
Dry P-traps.
A September classic.

The school closes on June 21 and reopens on September 1. Seven weeks without water through the drains — every drain trap in the school is dry. First week of classes: the whole school stinks, fruit flies in the kitchen, teachers calling for the maintenance staff. Green Drain™ solves the classic problem.

No chemicalsMaintenance-free30s installation5-year lifespan
7 weeks
Summer closing
0
Water in the P-trap
0
Fragrance in September
5 years
Life
Problem & solution

What happens in a school over the summer.

No children, no kitchen, no use of the washrooms. A trap with no water flowing through it runs dry within two to four weeks, so after seven weeks of holidays practically every one is dry. Odours build up, flies multiply in the biofilm, and on the first day of September it all greets the teachers and the children.

Without Green Drain™

  • P-traps in all washrooms will be drained by the end of July.
  • Fruit and drain flies (Drosophila, Psychoda) reproduce unimpeded in the biofilm.
  • Kitchen blocks open before classes — flies and smells greet the kitchen staff.
  • Parents complain: "It stinks like a toilet. What have you been doing all summer?"
  • The maintenance staff must perform a preventive flush of every drain before classes begin — labour cost.

With Green Drain™

  • A passive barrier that works dry or wet — it doesn't matter.
  • Chemical-free watering — safe for schools and daycares
  • Maintenance-free — expected service life of about 5 years; install and forget
  • Resistant to school cleaning agents (chlorine, soaps, floor cleaners)
  • Quiet — no gurgling or noises from the sewer even at high flow.
Croatian School Network

Verified figures from the CBS.

According to the State Statistical Office, Croatia has 891 elementary schools (with 1,062 branch schools) and 447 secondary schools with 770 school units. That's over 1,300 facilities that close seasonally — all of them facing the same problem of dried-up drains.

891
Elementary Schools (DZS 2023/2024)
447
High Schools (DZS 2024/2025)
1,062
Branch schools within the elementary school (DZS)
7 weeks
Summer standby — P-traps are drying out
770
High School School Units (DZS)
0
Chemicals, safe for children
Data Sources and Regulatory Framework (2024–2025 data)

Statistical data were taken from official sources: State Statistical Office (data.dzs.hr) Croatian Institute of Public Health (hzjz.hr), Ministry of Labor, Pension System, Family and Social Policy (mrosp.gov.hr), Agency for Science and Higher Education (azvo.hr), Ministry of Tourism and Sports (mint.gov.hr). Regulatory framework: EUR-Lex for EU directives and regulations — Regulation (EU) 2017/745 (MDR), Regulation (EC) No 178/2002 (general principles of food law), Regulation (EC) No 852/2004 (food hygiene — HACCP obligation), Regulation (EC) No 1935/2004 and Regulation (EU) No 10/2011 (food contact materials), Regulation (EU) No 528/2012 (BPR), Directive 2014/34/EU (ATEX). Standards: EN 1253-1 (floor P-traps, water seal ≥50 mm), EN 1253 Parts 6/7/8 (gullies with a water seal below 50 mm, with mechanical closure, and combined types; 2023 editions), ASSE 1072-2020 (floor drain trap seal protection devices) and NSF/ANSI 2 (food equipment). HACCP International RG-04 is a private certification programme operated by HACCP International, not an official certification issued by a public authority. Tourism data taken from the DZS publication for H1 2025, healthcare data from the HZJZ report 2024, data for education from DZS publications for the 2023/2024 and 2024/2025 school years, data for nursing homes from the MROSP report, and announcements of EU-funded construction in 2025. Revision date: May 2026.

Implementation

The whole school in one afternoon.

Ideally: the end of August, before classes start. A typical school — half a day's work for one technician.

01

Audit

The technician maps all drains throughout the facility — classrooms, toilets, kitchen and sports hall.

02

Offer

A written proposal for the principal and the maintenance team, covering boarding accommodation where there is any.

03

Test

We fit three samples at the critical points and your maintenance team judges the result.

04

The whole school

Half a day's work, carried out in the week before term starts.

Model Recommendation

Recommended sizes by type of room.

Croatian schools are built according to EN 1253. Most elementary schools built after 2000 have 50–58 mm traps in the washrooms. Older buildings (1950–1980) have a mix of 55–65 mm/80. Gymnasiums always have larger traps (75–85 mm–100) due to shower stalls for over 20 students at the same time.

Green Drain™ Recommended for your industry.

  • Primary school washrooms (new build)GD 2The most common size in Irish schools.
  • Shower rooms in sports hallsGD 3 (primary schools) or GD 3.5 (medium-sized with two halls)
  • School kitchen (meal preparation)GD 4Standard for kitchens producing 200–500 meals a day.
  • Dormitories (rooms + shared bathrooms)GD 2 or GD 3Closed all summer — the seal still holds.
💬 Not sure of the exact size? Send us a photo of your sink drain — our technical team will respond with a written recommendation within the same business day, free of charge.
Check out Green Drain™ → Request a quote
GD 2
50–58 mm · toilet blocks, crèches
GD 2.5
55–65 mm · older converted buildings
GD 3
75–85 mm · standard shower rooms
GD 3.5
89–100 mm · large shower rooms
GD 4
102–110 mm · kitchens, dormitories
GD 6
150–156 mm · central drain
Complete solution

Three products.
One protection portfolio.

Green Drain™ doesn't work alone — for maximum drain control it's combined with GD Uri-Tabs™ (urinals) and GreenSwirl™ (drain unblocking).

Ready for Free audit?

We come to the site, map the drains, and provide a written recommendation — no cost, no obligation.