The Right IP Rating for Water Infrastructure

For most underground water utility environments, IP67 is the correct specification. Here is the straightforward breakdown before we go deeper:

• IP65: Complete dust protection and resistance to low-pressure water jets from any direction, covering the low-pressure water jets scenario in most outdoor installations. Use this for above-ground pump stations, covered outdoor areas, and control rooms facing rain but no flooding.
• IP67: Complete dust protection and temporary immersion protection up to 1 metre for 30 minutes. The correct minimum standard for water tunnels, reservoir chambers, dam galleries, and any confined space where flooding is a realistic risk.
• IP68: Complete dust protection and continuous submersion beyond 1 metre. Reserve this for permanently submerged installations such as wet wells and below-waterline tank walls. The manufacturer should specify the exact depth and duration.

Key point:  IP ratings are not cumulative beyond IP66. An IP67 product has been tested for immersion, not high-pressure water jets. IP66 tests jets but not immersion. They are different tests, covering different risks. This matters particularly in a marine environment or offshore setting where both conditions can occur.

Understanding IP Ratings: What the Numbers Actually Mean

IP stands for Ingress Protection. The ingress protection rating system is defined by international standard IEC 60529, published by the International Electrotechnical Commission. This standard classifies how well an electrical enclosure protects electrical equipment against intrusion from solid particles and liquids, giving engineers and buyers a precise, test-based number. While IP ratings are familiar from consumer electronics and portable electronics such as smartphones and wearables, the stakes in industrial water infrastructure are considerably higher than a dropped phone. Understanding waterproof IP ratings properly means knowing what the number actually was tested against, rather than relying on a vague marketing term like ‘waterproof’ or ‘water-resistant’.

The IP code, also called the IP protection code, consists of two digits. The first digit runs from 0 to 6 and covers protection against solid objects, with 6 meaning complete protection against dust, also described as dust-tight or dust-tight in different standards documents, and 5 meaning dust protected but with limited dust ingress permitted. The second digit runs from 0 to 9 and covers liquid ingress protection, from no protection at 0 through to high-temperature, high-pressure spray at 9.

For water infrastructure lighting, nearly all relevant products carry a first digit of 6, meaning total dust protection across the board. The entire decision comes down to that second digit and what water test condition it represents.

Definition:  IP stands for Ingress Protection. The IP rating system, defined under IEC 60529, classifies how well electrical enclosures resist intrusion from solid objects and liquids. Ratings cannot be self-declared by manufacturers. Independent laboratory testing and verification are required for a valid IP certification.

IP65, IP66, IP67 and IP68 Explained for Water Infrastructure

IP65: For Outdoor Installations Facing Rain and Dust

IP65 rating provides complete dust protection and resistance to low-pressure water jets from any direction. The test uses 12.5 litres per minute of water directed at the product from a distance of 2.5 to 3 metres. This covers heavy rain, garden hose spray, and light washdown in outdoor environments.

What IP65 does not cover is any form of submersion or pooling water. For water infrastructure, this rating suits external structures, outdoor pump station housings, control room fittings in dry zones, and covered outdoor areas where rain is the main water exposure risk. It is not appropriate for any underground location where water accumulation is possible.

IP66: For High-Pressure Washdown Environments

IP66 tests protection against powerful water jets at 100 litres per minute and 100 kPa of pressure. This covers high-pressure water jets and high-pressure industrial cleaning, heavy seas, and environments where pressure hoses are used regularly as part of maintenance routines.

This is the rating most commonly misunderstood in relation to IP67. IP66 protects against high-pressure water exposure but does not cover immersion. IP67 covers temporary immersion but not high-pressure jets. A fitting that holds perfectly well under static water pressure may still fail if subjected to the directional dynamic force of a powerful water jet. For locations requiring protection against both conditions, look for a product carrying dual IP66/IP67 certification on its test report.

IP67: The Standard for Underground Water Infrastructure

IP67 is the ingress protection rating that covers the vast majority of water utility tunnel and reservoir applications. The test submerges the product to a depth of 1 metre for 30 minutes with no harmful water ingress permitted.

In practical terms, this means the fitting can survive temporary flooding, accidental submersion, high humidity, condensation, and the standing water that accumulates in underground confined spaces after access or heavy rain events. For water tunnels, reservoir access tunnels, dam wall inspection galleries, hydro plant passages, and any underground corridor where flooding is possible but not permanent, IP67 is the correct and sufficient specification.

MineGlow’s x-Glo LED strip lighting carries IP67 certification as standard. This rating has supported more than 20 kilometres of LED strip installations in water utility tunnels, reservoir passages, and dam galleries across the UK and Australia, and over 200km of lighting in very damp, high-dust mining environments.

IP68: For Permanently Submerged Equipment

IP68 is required when a fitting will be permanently below the waterline with no prospect of periodic drying. Products at this rating use high-quality rubber seals and hermetic enclosures designed for sustained water pressure. The test specifies continuous immersion beyond 1 metre, but unlike the other ratings, the exact depth and duration are set by the manufacturer and vary between products. One supplier’s IP68 may be tested at 1.5 metres for 30 minutes. Another may be tested at 5 metres for continuous operation. Always request the manufacturer’s test specification, not just the rating label.

IP68 is appropriate for wet wells in pumping stations, when installed below the waterline, and any installation where the fitting cannot be removed from water contact between maintenance visits. Products rated IP68 typically carry a 10 to 40 per cent cost premium over equivalent IP67 products. For applications where IP67 is sufficient, that premium adds no real-world benefit. Specifying a higher IP rating than needed costs more without improving performance.

IP Rating Comparison Table for Water Infrastructure Lighting

Use this IP rating chart as a quick reference when specifying lighting for water utility projects:

Choosing the Correct IP Rating by Location

The right IP rating is not about choosing the highest number. Choosing the wrong IP rating creates real problems. It is about matching the test condition to the actual conditions the fitting will face. Here is how that plays out across common water utility environments.

Fresh water tunnels: Underground inspection tunnels experience constant humidity, condensation, and periodic flooding. IP67 is the correct minimum specification. IP65 will not cope with pooling water, and IP68 adds unnecessary cost unless the fitting sits below the tunnel’s flood level.

Reservoir access tunnels and chambers: Similar conditions to water tunnels. IP67 for the main inspection routes. Consider IP68 for fittings at the lowest chamber levels where standing water may remain between visits.

Dam walls and hydro plant galleries: High humidity and water seepage through ageing concrete structures are the main risks. Direct flooding is less likely in maintained galleries. IP67 covers the realistic worst-case scenario in these environments.

Pump stations and washdown areas: External pump station structures and control rooms in dry areas suit IP65. Wet areas involving high-pressure cleaning require IP66. Any zone at risk of flooding requires IP67.

Sewage tunnels and wastewater confined spaces: These environments require both water ingress protection and explosion-proof certification. Methane and hydrogen sulphide gas mean standard LED strip lights are not appropriate, regardless of IP rating. MineGlow’s SafeGlo EXm range carries both IP67 ingress protection and IECEx/ATEX certification for Zone 1 and Zone 2 classified areas. See MineGlow’s explosion-proof lighting and hazardous LED lighting pages for full details.

Wet wells: Permanent water contact requires IP68. Confirm the manufacturer’s specified depth and duration before installing, since IP68 is not a single fixed standard.

What the IP Rating Does Not Cover

Ingress protection ratings test for dust and water intrusion under controlled lab conditions using fresh water. They do not address corrosion resistance in saltwater or chemically treated water, UV degradation in outdoor environments, high temperature cycling performance, or resistance to chemicals such as hydrogen sulphide or chlorine found in sewage infrastructure.

For water infrastructure lighting, the IP rating is your starting point, not your complete specification. Enclosure material quality, seal type, operating temperature range, and corrosion-resistant coatings all matter alongside it. MineGlow’s x-Glo LED strips use silicone or PVC extrusions with nanotechnology-built dirt and chemical resistance for corrosive underground environments, operating from -30 to +80 degrees Celsius. Note that food processing and pharmaceutical environments use IP69K for high-temperature, high-pressure steam cleaning, which is a separate rating outside the scope of water infrastructure.

Frequently Asked Questions

Is IP67 waterproof?

IP67 provides temporary immersion protection up to 1 metre for 30 minutes. Products at this level are water-resistant against submersion for that defined period. It covers flooding and accidental submersion but not permanent or continuous water contact. For prolonged underwater installations, IP68 is required. The term ‘waterproof’ is a marketing label without a fixed technical meaning. IP ratings give you specific, tested waterproof protection levels and reliable protection that are far more useful than generic waterproof claims or vague water protection assurances.

Does IP68 replace IP67?

No, and this is one of the most common misconceptions. IP ratings above IP66 are not cumulative. An IP68 product has been tested for deep immersion, not for high-pressure water jets. An IP67 product has been tested for temporary immersion, but not for powerful jets. If your installation involves both flooding risk and high-pressure cleaning, you need a product with dual IP66/IP67 certification confirmed on the test report.

Can manufacturers self-declare IP ratings?

No. Valid IP ratings under IEC 60529 must be independently tested and verified by an accredited testing laboratory. Always request the test report, not just the product data sheet. MineGlow’s x-Glo IP67 certification is independently verified, and test reports are available on request.

What IP rating do I need for a sewage tunnel in Australia or the UK?

Sewage tunnels require IP67 for water ingress protection as a minimum. They also require IECEx certification in Australia and ATEX certification in the UK for any classified hazardous zone where methane or hydrogen sulphide may be present. IP rating and explosion-proof certification are separate requirements, and neither replaces the other. MineGlow’s SafeGlo EXm range meets both.

What happens if an LED strip is cut on site?

Cutting an IP-rated LED strip without properly sealing the cut end compromises the ingress protection rating immediately. The rest of the strip retains its rating, but the exposed cut end does not. Always use the manufacturer’s specified connector kits and end caps to reseal any cut point. MineGlow provides repair kits and connector kits for this purpose.