The verdict in three sentences
For a Rotterdam water treatment and pool service company, a field app for routes, water test readings, legionella sampling and product billing realistically takes 5 to 9 months from the first workshop to full adoption. The date that matters most is the cutover, which should fall between October and March, outside the outdoor pool season and the summer peak in hotel and leisure pools. Start discovery in the autumn and go live in late winter, or accept a cutover after the summer.
What the app must cover
With 30 technicians across Rotterdam, The Hague, Delft and the Westland, a mix of public swimming pools, hotel and spa pools, care homes and commercial buildings, the app must plan routes, capture readings (pH, free and combined chlorine, temperature) at every visit, log legionella samples sent to the lab, record chemicals dosed and trigger billing. In the Netherlands, legionella prevention for priority installations is governed by the Drinking Water Decree (Drinkwaterbesluit), and public pools have their own water quality and hygiene rules, so the app must keep risk analysis actions, sampling records and lab results available for an inspection.
| Module | Complexity | 2026 duration ballpark |
|---|---|---|
| Route planning across 700 to 1,600 contracts | Medium | 4 to 6 weeks of development |
| Readings and photos at every visit | Low | 2 to 3 weeks |
| Legionella sampling and lab results | Medium | 3 to 4 weeks |
| Offline mode in plant rooms | Medium | 2 to 4 weeks |
| Chemicals dosed and van stock | High | 4 to 6 weeks |
| Billing and accounting export | High | 3 to 5 weeks |
The plan phase by phase
These are 2026 market ballparks for a budget of 50,000 to 130,000 EUR. Phases overlap, so the total is 5 to 9 months rather than the raw sum.
| Phase | Realistic duration | Deliverable | Common cause of delay |
|---|---|---|---|
| Discovery | 3 to 5 weeks | Scope, wireframes, billing rules | Chemical billing rules never written down |
| Detailed design | 3 to 4 weeks | Technician journey tested in the field | Technicians unavailable for workshops |
| Development in sprints | 12 to 20 weeks | Testable release every 2 weeks | Scope added mid project |
| Data migration | 2 to 4 weeks, in parallel | Contracts, installations, sampling history | Duplicate client records |
| Pilot with 5 technicians | 3 to 4 weeks | Field adjustments | No mobile signal in basements |
| Full rollout | 1 to 2 weeks | 30 technicians live | Cutover attempted in May |
The number one cause of delay is scope creep: a client portal, quotes for repair work or van tracking appear mid project. Keep them for release two. The second is the season: a cutover in May, when outdoor pools reopen, nearly always ends with technicians back on paper.
As a nearshore benchmark, Kolonell's prices for a business application are 6,100 to 10,670 EUR (4,000,000 to 7,000,000 FCFA) for a medium app and 10,670 to 22,870 EUR and up (7,000,000 to 15,000,000 FCFA and up) for a complex one. A routes, readings and sampling app with chemical billing usually sits in the complex bracket.
Mini case study
Illustrative example: Joost manages a water treatment company in Rotterdam with 30 technicians and 1,000 contracts. Each technician spends 30 minutes a day copying readings and chemicals into the office system, over 210 days, or 105 hours a year and 3,150 hours for the team. At a loaded cost of 45 EUR an hour, that is 141,750 EUR a year. He starts discovery in early October, builds from November to February, pilots in February and goes live on 1 March. Had he started in April, he would have faced a risky June cutover or a wait until October, roughly 70,000 EUR more of manual entry.
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FAQ
Can it be done in under 5 months?
Yes, with a scope limited to routes and readings, a first release can run in 10 to 12 weeks. Chemical billing, van stock and the client portal then move to release two.
Why avoid a cutover between April and September?
That is when outdoor pools reopen and hotel pools run at full load. A new tool needs 2 to 3 weeks of adjustment that teams cannot spare in season.
Does the app need to work offline?
Yes, plant rooms in basements often have no signal. Offline mode adds 2 to 4 weeks of development but prevents lost readings.
How do we keep records ready for a legionella inspection?
The app should store every sample with date, location, technician, lab result and follow up action, and export the logbook per installation. That module is a few days of work if planned at discovery.
What should we budget after go live?
A 2026 ballpark is 10 to 20 % of the build cost per year. Kolonell's maintenance plans run from 53 EUR to 183 EUR per month.
Let's scope your project. Tell us your number of technicians, contracts and your ideal cutover date, and we will build a realistic plan and budget. Detailed quote within 48 h. WhatsApp +221 77 596 93 33.
Mohamed Bah
Fondateur, Kolonell
Passionate about digital and entrepreneurship in Africa, Mohamed has been helping Sénégalese businesses with their digital transformation since 2020. Founder of Kolonell, he believes every SME deserves a professional and accessible online présence.
