Material Insights · Understanding the Material World

Water and sanitation and Water treatment chemicals

Surface water for piped supply is coagulated, usually with alum or polyaluminium chloride, and chlorinated to leave a residual at the tap, and sewage plants use polymers to dewater sludge; so the build-out of taps under Jal Jeevan Mission and of sewage treatment in India sets a steady, rule-driven demand for these chemicals.

Water and sanitation (industry) and Water treatment chemicals (chemical): 3 relationships.

How they are linked

1. Coagulants, disinfectants and flocculants

Physical flow · Strong · Treatment chemicals → water utilities and sewage plants

Surface water must be coagulated to remove turbidity and disinfected to kill pathogens before it is safe to supply, and sludge from sewage plants must be thickened and dewatered; three enterprise types in water and sanitation depend on these chemicals, rated up to 5 of 5.

  • 5 of 5 criticality for water utilities (coagulants)
  • 20 to 40 mg/L typical alum dose for surface water with turbidity of 50 to 200 NTU (CPHEEO manual, as summarised)
  • 1 to 2.5 mg/L typical chlorine dose in a conventional treatment plant

Sewage treatment operators rate flocculants for sludge dewatering 4 of 5 and chemical suppliers 3 of 5. Doses change with the season and the raw water, so plants set them by jar test; polyaluminium chloride generally needs a lower dose than alum and makes less sludge, so the choice between them turns on delivered cost per litre treated rather than price per tonne.

Enterprise types that depend on it:

  • Water utilities (municipal boards and private operators): coagulants (criticality 5 of 5)
  • Sewerage and sewage-treatment plant operators: flocculants for sludge dewatering (criticality 4 of 5)
  • Water-treatment chemical suppliers: coagulants, flocculants and antiscalants (criticality 3 of 5)

Sources: Material Insights; Infralens (summary of the CPHEEO manual, Ministry of Housing and Urban Affairs)

2. Residual chlorine standard

Policy · Strong · Drinking water standards → disinfectant demand

Indian standards require chlorinated supplies to carry free chlorine to the tap so that contamination in the pipes is neutralised, which fixes a minimum, continuous use of disinfectant.

  • 0.2 mg/L minimum free residual chlorine, tested at the consumer end, where water is chlorinated (IS 10500:2012)
  • 0.5 to 1.0 mg/L residual chlorine at the treatment plant outlet (CPHEEO manual, as summarised)

IS 10500 raises the minimum to 0.5 mg/L where protection against viral infection is needed, and the CPHEEO manual treats a residual below 0.2 mg/L as a contamination risk to investigate. Plants dose about 1 to 2.5 mg/L to cover chlorine demand of about 0.5 to 1.5 mg/L plus the residual, so the quality of raw water and the network, not only the volume supplied, drives disinfectant use.

Sources: Infralens (summary of the CPHEEO manual, Ministry of Housing and Urban Affairs); Bureau of Indian Standards

3. Tap water and sewage build-out

Transition · Rising · New taps and treatment plants → chemical demand

Each new piped supply scheme and sewage treatment plant adds a continuous chemical load, so public programmes that extend piped water and sewage treatment grow the market for coagulants, chlorine and polymers.

  • 15.72 crore rural households with tap water, about 81% of the total, October 2025
  • 72,368 MLD sewage generated in India against 31,841 MLD of installed treatment capacity (CPCB, reported 2021)

Jal Jeevan Mission had a central outlay of about ₹2.09 lakh crore, and its water quality network had 2,843 laboratories in October 2025. On sewage, only about 20,235 MLD of capacity was actually used in the 2021 data, so treating all sewage generated would mean handling about three and a half times that volume, with matching growth in flocculant and disinfectant use.

Sources: Press Information Bureau, Ministry of Jal Shakti; Down To Earth

For investors

Key learnings

  1. Water treatment chemical demand is steady and rule-driven, since surface water must be coagulated and chlorinated supplies must keep a 0.2 mg/L residual at the tap whatever the economic cycle.
  2. The growth comes from coverage: India's tap water and sewage treatment build-out adds plants that each need chemicals for decades.
  3. Polyaluminium chloride needs a lower dose than alum and makes less sludge, which gives makers of higher-value coagulants an argument based on cost per litre treated.

What to track

  • Sewage treatment capacity installed and utilised: Growth in flocculant and disinfectant demand (Yearly · CPCB, Ministry of Housing and Urban Affairs (AMRUT))
  • Jal Jeevan Mission functional tap connections: Demand for coagulants and chlorine in rural schemes (Monthly · Jal Jeevan Mission dashboard)
  • Chlorine and caustic soda prices in India: Cost of disinfection for utilities (Monthly · Alkali Manufacturers Association of India, Chemical Weekly)

For policymakers

Key learnings

  1. Taps are only safe if schemes keep buying and dosing chemicals, so operation and maintenance budgets matter as much as capital outlay.
  2. Residual chlorine testing at the tail end of networks is the simplest check that treatment is working; Jal Jeevan Mission's 2,843 laboratories give the means to do it.
  3. India's sewage treatment gap, with installed capacity under half of sewage generated, implies large future chemical needs that should be planned into tenders.

What to track

  • Share of water samples failing residual chlorine or bacteriological tests: Whether treatment and dosing are adequate (Monthly · Jal Jeevan Mission WQMIS)
  • Sewage treatment capacity utilisation: Whether new plants actually run and buy chemicals (Yearly · CPCB)

India

Over 81% of rural households had tap water by October 2025 under Jal Jeevan Mission, and installed sewage treatment capacity covered under half of sewage generated in CPCB data reported in 2021, so India's water chemical demand is set to grow with coverage.

Sources

  1. Water and sanitation: materials, Material Insights (2026)
  2. CPHEEO Manual on Water Supply and Treatment: chapter summaries, Infralens (summary of the CPHEEO manual, Ministry of Housing and Urban Affairs)
  3. Jal Jeevan Mission: progress note, October 2025, Press Information Bureau, Ministry of Jal Shakti (2025)
  4. India's sewage treatment plants treat only a third of the sewage generated daily: CPCB, Down To Earth (2021)
  5. IS 10500:2012 Drinking water: specification (second revision), Bureau of Indian Standards (2012)