Good water purifier billing software in India should do more than print GST invoices. It should also link each customer to their machine, installation date, AMC expiry and service history. A generic billing app is enough if you only need invoices and GST filing. If AMC and service customers are a big part of your income, you need software built for sales, service and AMC.
Why water purifier billing software needs to go beyond a basic billing app
A dealer earns from three streams: purifier sales, filters and spare parts, and service or AMC. A billing-only tool records the bill for each, but it will not tell you that a customer’s AMC ends next month.
Domestic RO/UV units typically cost roughly ₹8,000-₹25,000, while domestic AMC usually runs about ₹1,500-₹4,500 a year, depending on brand and city. The sale happens once, but the AMC can come back every year if you remember to ask.
Illustrative example (not a statistic): say you have 150 AMC customers at ₹2,500 a year. If 90 renew, you earn ₹2,25,000. If timely reminders bring that to 120 renewals, you earn ₹3,00,000. That is ₹75,000 more, before GST, from customers you already have. Your own numbers will differ, but the exercise shows why renewal tracking matters.
GST billing basics for water purifier dealers
Purifiers usually fall under HSN 8421. Spare parts need an HSN check item by item. Service and AMC are services, usually under SAC 9987. Rates have historically been 18%, but GST slabs were revised in 2025, so do not rely on memory or old invoices. Check each item on the CBIC website (cbic.gov.in) or the GST Council rate notifications, then confirm with your CA before saving rates in your software.
Thresholds to know
- Registration: generally ₹40 lakh turnover for goods and ₹20 lakh for services, though state limits vary. Verify the current limits for Tamil Nadu.
- E-invoicing: applies above an aggregate turnover threshold, last known as ₹5 crore. Verify the current figure. Most small dealers are below it, but know it before you grow past it.
Mandatory invoice fields
Every invoice needs your GSTIN (and the buyer’s for B2B), HSN or SAC, place of supply and a serial invoice number. Within Tamil Nadu, split tax into CGST and SGST. For inter-state sales, use IGST. Your software should also produce GSTR-1 and GSTR-3B-ready reports.
Purifier plus installation on one bill
This is a composite versus mixed supply question. If items are naturally bundled, the main item usually decides the tax treatment. If they are separately priced, rules can differ. Many dealers show lines separately for clarity, but ask your CA how to treat your bills.
| Line (illustrative, assuming 18%) | Code | Amount | CGST 9% + SGST 9% |
|---|---|---|---|
| RO+UV purifier | HSN 8421 | ₹14,000 | ₹1,260 + ₹1,260 |
| Installation | SAC 9987 | ₹500 | ₹45 + ₹45 |
| 1-year AMC (2 services), sold separately | SAC 9987 | ₹2,500 | ₹225 + ₹225 |
The first two lines total ₹17,110 with tax. The AMC line alone comes to ₹2,950. The 18% rate is only for the example, so confirm the current rate.
What dealers use today and where it falls short
Dealers commonly use Tally, Vyapar, Zoho Books, Busy, Excel, paper registers and WhatsApp. These tools are generally good at accounts and invoicing, and they work well for many businesses.
What generic tools usually don’t focus on is the service side: linking the installation date to a customer, AMC expiry alerts, filter-change schedules and technician job tracking. “Tally is enough” is true for accounts and your CA. It is not true for follow-ups. Many dealers keep Tally for the books and add a CRM for customers.
Features to look for in water purifier billing software
- GST invoices and quotations with HSN/SAC support.
- Machine history: model, serial number, installation date and AMC end date per customer.
- AMC management: alerts (for example 30, 15 and 7 days before expiry), renewal tracking and a written scope. A sample line: “AMC, domestic RO/UV, 12 months, 2 services, filters excluded, ₹2,500 + GST.”
- Service tracking: technician, job status, parts used and payment collected.
- Inventory: purifiers, membranes, sediment/carbon filters, UV lamps and pumps, with reorder levels and serial numbers.
- Follow-ups: quotations and dues, plus UPI links or QR on invoices.
- WhatsApp reminders via the official Business API, which needs Meta-approved templates and charges apply (verify current pricing). It avoids the ban risk of bulk messages from a personal number.
- Basics: mobile access for technicians, data import/export, backups and role-based access.
Generic billing app vs billing + CRM: a comparison
| Capability | Generic billing app (typical) | Billing + CRM for dealers (what to look for) |
|---|---|---|
| GST invoicing | Usually strong | Should match generic tools |
| AMC expiry alerts | Usually not a focus | Alerts and renewal tracking |
| Service scheduling | Usually not a focus | Jobs, technicians, status |
| Machine history | Often limited | Model, serial, install date |
| WhatsApp reminders | Varies | Service and AMC reminders |
| Stock | Basic item stock | Parts with reorder levels |
If you only need accounts and filing, a generic tool may be enough. A CRM pays off once you have AMC and service customers.
Where Nixie CRM fits
Nixie CRM by Shiny Software Services is built for water purifier dealers. Against the checklist above, it covers customer management, sales tracking, inventory, GST invoice generation, AMC management, service tracking, quotation and payment follow-ups, and WhatsApp API reminders. Before you buy, ask Nixie, as you would any vendor, about Tamil language support, price per user and how it behaves on weak internet. Test these in the trial rather than assuming. For a wider view, see our water purifier dealer management software guide.
How to set up billing and AMC tracking
- Confirm HSN/SAC and rates with your CA, then set up your invoice format.
- Clean your Excel sheet (name, phone, address, model, install date, AMC end date), import 20 rows, check them, then import the rest.
- Add stock with reorder levels. Set filter-service intervals, typically 6-12 months depending on TDS and usage.
- Turn on AMC alerts and WhatsApp reminders, and assign technicians.
- Every week, review dues, upcoming renewals and top-selling parts.
More detail is in our RO service management software guide.
Tamil Nadu dealer considerations
Hard water and high TDS are common in many areas, including Chennai, Coimbatore, Madurai and Tiruppur. This often shortens filter life and creates seasonal service rushes. Tag each customer by area and water source (borewell, municipal or tanker) so you can plan technician routes and filter stock before a rush.
Ask vendors whether support and onboarding are available in Tamil, whether technicians can use the app on a phone in the field, and how it works on weak internet in smaller towns. Customer messages in Tamil also need Meta-approved templates in that language, so ask how that works.
Common billing and AMC mistakes that cost dealers money
- No installation date: you cannot find renewal leads, so revenue quietly lapses.
- Wrong HSN/SAC: this can mean wrong tax, notices or mismatched returns.
- AMC without written scope: disputes over which parts are covered lead to free work or lost customers.
- Unfollowed quotations: the customer buys from whoever calls back first.
- Bulk messages from a personal WhatsApp number: the number can be banned, and with it your customer contact.
- Customer data in staff phones: when staff leave, the data goes with them. Use role-based access.
- Assuming cloud is unsafe: check backups, access control and export instead.
For wider ideas, read how to grow a water purifier dealership.
How to choose water purifier billing software and trial it without risk
Use real data in the trial: create 10 real invoices, import a sample Excel file, create one AMC and one service job, and send a test reminder. Ask about per-user cost, data export and support response. If anything fails with your own data, you have your answer before paying.
Ready to test it? Start your 7-day free trial of Nixie CRM or explore the product at nixie.in.
FAQ
Which GST rate and HSN code apply to water purifiers and spare parts?
Purifiers usually fall under HSN 8421, and the rate has historically been 18%. Parts need an HSN check item by item. Because slabs were revised in 2025, check current rates on the CBIC site or with your CA.
Is Tally or Vyapar enough for a water purifier dealer, or do I need a CRM?
For accounts and invoices, they can be enough. If you manage AMC renewals, filter schedules and technician jobs, a CRM built for service follow-ups is more useful.
Can billing software track AMC renewals and send WhatsApp reminders?
Software built for dealers can. Generic billing apps usually don’t focus on it. WhatsApp reminders through the official Business API need Meta-approved templates, and charges apply.
How do I move my old customer data from Excel into billing software?
Clean the sheet first with name, phone, address, model, install date and AMC end date. Import a small sample, check it, then import the rest.
What is the difference between SAC and HSN on a water purifier service invoice?
HSN classifies goods, such as the purifier or filters. SAC classifies services, such as repair or AMC, usually SAC 9987. A bill with both should show each under its own code.
Is cloud-based billing software safe for my customer data?
It can be, if the vendor provides backups, access control and data export. Check these before committing, and limit staff access by role.